Stacked auxiliary field-effect transistor configurations for radio frequency applications

ABSTRACT

Disclosed herein are switching or other active FET configurations that implement a main-auxiliary branch design. Such designs include a circuit assembly for performing a switching function that includes a branch including a main path in parallel with an auxiliary path, both the main path and the auxiliary path having a plurality of field-effect transistors. The circuit assembly also includes a first gate bias network connected to the main path. The circuit assembly also includes a second gate bias network connected to a first subset of the plurality of FETs of the auxiliary path. The circuit assembly also includes a third gate bias network connected to a second subset of the plurality of FETs of the auxiliary path, the second gate bias network and the third gate bias network being independently configurable to improve linearity of the switching function.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/399,635 filed Sep. 26, 2016 and entitled “Master-Slave Field-EffectTransistor Configurations for Radio Frequency Applications,” which isexpressly incorporated by reference herein in its entirety for allpurposes.

BACKGROUND Field

The present disclosure generally relates to transistor and switchconfigurations for wireless communication.

Description of Related Art

In electronics applications, field-effect transistors (FETs) can beutilized as switches and in amplifiers. Switches can allow, for example,routing of radio-frequency (RF) signals in wireless devices. FETs inswitches and other circuits can introduce distortions into signals dueat least in part to harmonics generated by the FETs.

SUMMARY

According to a number of implementations, the present disclosure relatesto a circuit assembly for performing a switching function, the circuitassembly having a branch including a main path in parallel with anauxiliary path, a first gate bias network connected to the main path,and a second gate bias network connected to the auxiliary path, thesecond gate bias network configured to improve linearity of theswitching function.

In some embodiments, the circuit assembly further includes a body biasnetwork coupled to the main path. In some embodiments, the body biasnetwork is further coupled to the auxiliary path.

In some embodiments, the main path comprises a plurality of field-effecttransistors. In some embodiments, the auxiliary path comprises aplurality of field-effect transistors.

In some embodiments, the branch is coupled between a series arm and areference potential node in a shunt configuration. In some embodiments,the second gate bias network is configured to reduce capacitivenonlinearity of the switching function.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region and the second gate biasnetwork is configured to bias the auxiliary path in a weak inversionregion. In some embodiments, the circuit assembly further includes abias feedback module configured to adjust a bias of the second gate biasnetwork based at least in part on a power or a frequency of an inputsignal to the branch. In some embodiments, the second gate bias networkis configured to bias the auxiliary path to generate third-orderharmonics or third-order intermodulation products that are opposite inphase to third-order harmonics or third-order intermodulation productsgenerated by the main path.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) switching configuration including an inputnode configured to receive an input signal; an output node configured toprovide an output signal related to the input signal; a main-auxiliarybranch coupled between the input node and the output node, themain-auxiliary branch including a main path having a main field-effecttransistor (FET) and an auxiliary path having an auxiliary FET, the mainpath coupled in parallel with the auxiliary path; a main gate biasnetwork configured to provide a main gate bias voltage to the main FET;and an auxiliary gate bias network configured to provide an auxiliarybias voltage to the auxiliary FET such that the auxiliary path generatesdistortions that are opposite in phase to distortions generated by themain path to reduce distortions through the main-auxiliary branch.

In some embodiments, the main FET is configured to operate in a stronginversion region responsive to the main bias voltage. In someembodiments, the auxiliary FET is configured to operate in a weakinversion region responsive to the auxiliary bias voltage.

In some embodiments, the main gate bias voltage is greater than theauxiliary gate bias voltage. In some embodiments, the main path furtherincludes a second main FET. In some embodiments, the main gate biasnetwork is further configured to provide the main gate bias voltage tothe second main FET.

In some embodiments, the auxiliary path further includes a secondauxiliary FET. In some embodiments, the auxiliary gate bias network isfurther configured to provide the auxiliary gate bias voltage to thesecond auxiliary FET. In some embodiments, the RF switchingconfiguration further includes a second auxiliary gate bias networkconfigured to provide a second auxiliary gate bias voltage to the secondauxiliary FET. In some embodiments, the second auxiliary gate biasvoltage is different from the auxiliary gate bias voltage. In someembodiments, the main gate bias network is further configured to providethe main gate bias voltage to the second auxiliary FET.

In some embodiments, the RF switching configuration further includes abody bias network configured to provide a body bias voltage to the mainFET and to the auxiliary FET. In some embodiments, the main gate biasnetwork is configured to provide two static voltages to the main FETcorresponding to on and off states. In some embodiments, the auxiliarygate bias network is configured to provide a dynamic voltage to theauxiliary FET. In some embodiments, the auxiliary gate bias network isconfigured to generate the auxiliary gate bias voltage responsive to apower of the input signal at the input node. In some embodiments, theauxiliary gate bias network is configured to generate the auxiliary gatebias voltage responsive to a frequency of the input signal at the inputnode.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) module including a packaging substrateconfigured to receive a plurality of devices; and a circuit assemblymounted on the packaging substrate, the circuit assembly including abranch including a main path in parallel with an auxiliary path, a firstgate bias network connected to the main path, and a second gate biasnetwork connected to the auxiliary path, the second gate bias networkconfigured to improve linearity of the switching function.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region and the second gate biasnetwork is configured to bias the auxiliary path in a weak inversionregion.

According to a number of implementations, the present disclosure relatesto a wireless device including a transceiver configured to processradio-frequency (RF) signals; an RF module in communication with thetransceiver, the RF module including a circuit assembly including abranch including a main path in parallel with an auxiliary path, a firstgate bias network connected to the main path, and a second gate biasnetwork connected to the auxiliary path, the second gate bias networkconfigured to improve linearity of the switching function; and anantenna in communication with the RF module, the antenna configured tofacilitate transmitting and/or receiving of the RF signals.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region and the second gate biasnetwork is configured to bias the auxiliary path in a weak inversionregion.

According to a number of implementations, the present disclosure relatesto a circuit assembly for performing a switching function, the circuitassembly including a branch including a main path in series with anauxiliary path; a first gate bias network connected to the main path;and a second gate bias network connected to the auxiliary path, thesecond gate bias network configured to improve linearity of theswitching function.

In some embodiments, the circuit assembly further includes a body biasnetwork coupled to the main path. In some embodiments, the body biasnetwork is further coupled to the auxiliary path.

In some embodiments, the main path comprises a plurality of field-effecttransistors. In some embodiments, the auxiliary path comprises aplurality of field-effect transistors.

In some embodiments, the branch is coupled between a series arm and areference potential node in a shunt configuration. In some embodiments,the second gate bias network is configured to reduce capacitivenonlinearity of the switching function.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region and the second gate biasnetwork is configured to bias the auxiliary path in a weak inversionregion. In some embodiments, the circuit assembly further includes abias feedback module configured to adjust a bias of the second gate biasnetwork based at least in part on a power or a frequency of an inputsignal to the branch. In some embodiments, the second gate bias networkis configured to bias the auxiliary path to generate third-orderharmonics or third-order intermodulation products that are opposite inphase to third-order harmonics or third-order intermodulation productsgenerated by the main path.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) switching configuration including an inputnode configured to receive an input signal; an output node configured toprovide an output signal related to the input signal; a main-auxiliarybranch coupled between the input node and the output node, themain-auxiliary branch including a main path having a main field-effecttransistor (FET) and an auxiliary path having an auxiliary FET, the mainpath coupled in series with the auxiliary path; a main gate bias networkconfigured to provide a main gate bias voltage to the main FET; and anauxiliary gate bias network configured to provide an auxiliary biasvoltage to the auxiliary FET such that the auxiliary path generatesdistortions that are opposite in phase to distortions generated by themain path to reduce distortions through the main-auxiliary branch.

In some embodiments, the main FET is configured to operate in a stronginversion region responsive to the main bias voltage. In someembodiments, the auxiliary FET is configured to operate in a weakinversion region responsive to the auxiliary bias voltage.

In some embodiments, the main gate bias voltage is greater than theauxiliary gate bias voltage. In some embodiments, the main path furtherincludes a second main FET. In some embodiments, the main gate biasnetwork is further configured to provide the main gate bias voltage tothe second main FET.

In some embodiments, the auxiliary path further includes a secondauxiliary FET. In some embodiments, the auxiliary gate bias network isfurther configured to provide the auxiliary gate bias voltage to thesecond auxiliary FET. In some embodiments, the circuit assembly furtherincluding a second auxiliary gate bias network configured to provide asecond auxiliary gate bias voltage to the second auxiliary FET. In someembodiments, the second auxiliary gate bias voltage is different fromthe auxiliary gate bias voltage. In some embodiments, the main gate biasnetwork is further configured to provide the main gate bias voltage tothe second auxiliary FET.

In some embodiments, the circuit assembly further includes a body biasnetwork configured to provide a body bias voltage to the main FET and tothe auxiliary FET. In some embodiments, the main gate bias network isconfigured to provide two static voltages to the main FET correspondingto on and off states. In some embodiments, the auxiliary gate biasnetwork is configured to provide a dynamic voltage to the auxiliary FET.In some embodiments, the auxiliary gate bias network is configured togenerate the auxiliary gate bias voltage responsive to a power of theinput signal at the input node. In some embodiments, the auxiliary gatebias network is configured to generate the auxiliary gate bias voltageresponsive to a frequency of the input signal at the input node.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) module including a packaging substrateconfigured to receive a plurality of devices; and a circuit assemblymounted on the packaging substrate, the circuit assembly including abranch including a main path in series with an auxiliary path, a firstgate bias network connected to the main path, and a second gate biasnetwork connected to the auxiliary path, the second gate bias networkconfigured to improve linearity of the switching function.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region and the second gate biasnetwork is configured to bias the auxiliary path in a weak inversionregion.

According to a number of implementations, the present disclosure relatesto a wireless device that includes a transceiver configured to processradio-frequency (RF) signals; an RF module in communication with thetransceiver, the RF module including a circuit assembly including abranch including a main path in series with an auxiliary path, a firstgate bias network connected to the main path, and a second gate biasnetwork connected to the auxiliary path, the second gate bias networkconfigured to improve linearity of the switching function; and anantenna in communication with the RF module, the antenna configured tofacilitate transmitting and/or receiving of the RF signals.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region and the second gate biasnetwork is configured to bias the auxiliary path in a weak inversionregion.

According to a number of implementations, the present disclosure relatesto a circuit assembly for performing a switching function that includesa branch including a main path in parallel with an auxiliary path; and agate bias network connected to the main path and to the auxiliary path,the main path and the auxiliary path each having different structuresthat are configured to improve linearity of the switching function.

In some embodiments, the gate bias network is configured to bias themain path in a strong inversion region and to bias the auxiliary path ina weak inversion region. In some embodiments, the gate bias network isconfigured to bias the auxiliary path to generate third-order harmonicsor third-order intermodulation products that are opposite in phase tothird-order harmonics or third-order intermodulation products generatedby the main path.

In some embodiments, the different structures include different wellimplants. In some embodiments, the different structures includedifferent halo implants. In some embodiments, the different structuresinclude different device geometries. In some embodiments, the differentstructures include different gate oxide thicknesses. In someembodiments, the different structures include different buried oxide(BOX) layer thickness. In some embodiments, the different structuresinclude different silicon thickness.

In some embodiments, the circuit assembly further includes a body biasnetwork connected to both the main path and the auxiliary path. In someembodiments, the main path and the auxiliary path are part of amulti-finger device.

According to a number of implementations, the present disclosure relatesto a circuit assembly for performing a switching function that includesa branch including a main path in series with an auxiliary path; and agate bias network connected to the main path and to the auxiliary path,the main path and the auxiliary path each having different structuresthat are configured to improve linearity of the switching function.

In some embodiments, the gate bias network is configured to bias themain path in a strong inversion region and to bias the auxiliary path ina weak inversion region. In some embodiments, the gate bias network isconfigured to bias the auxiliary path to generate third-order harmonicsor third-order intermodulation products that are opposite in phase tothird-order harmonics or third-order intermodulation products generatedby the main path. In some embodiments, the branch further includes asecond auxiliary path in series with the main path and the auxiliarypath.

In some embodiments, the auxiliary path includes a plurality offield-effect transistors. In some embodiments, the main path includes aplurality of field-effect transistors. In some embodiments, a firstsubset of the plurality of field-effect transistors of the auxiliarypath is coupled to an input of the branch, a second subset of theplurality of field-effect transistors of the auxiliary path is coupledto an output of the branch, and the plurality of field-effecttransistors of the main path are coupled between the first subset andthe second subset of the plurality of field-effect transistors of theauxiliary path.

In some embodiments, the circuit assembly further includes a body biasnetwork connected to the main path and to the auxiliary path.

In some embodiments, the different structures include at least one ofdifferent well implants, halo implants, device geometries, gate oxidethicknesses, buried oxide layer thicknesses, or silicon thicknesses. Insome embodiments, the main path and the auxiliary path are part of amulti-finger device.

In some embodiments, the branch is coupled between a series arm and areference potential node in a shunt configuration. In some embodiments,the second gate bias network is configured to reduce capacitivenonlinearity of the switching function.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) module that includes a packaging substrateconfigured to receive a plurality of devices; and a circuit assemblymounted on the packaging substrate, the circuit assembly including abranch including a main path in parallel with an auxiliary path, and agate bias network connected to the main path and to the auxiliary path,the main path and the auxiliary path each having different structuresthat are configured to improve linearity of the switching function.

In some embodiments, the gate bias network is configured to bias themain path in a strong inversion region and to bias the auxiliary path ina weak inversion region. In some embodiments, the circuit assembly isimplemented in a series arm of a multi-pole, multi-throw switch.

According to a number of implementations, the present disclosure relatesto a wireless device that includes a transceiver configured to processradio-frequency (RF) signals; an RF module in communication with thetransceiver, the RF module including a circuit assembly including abranch including a main path in series with an auxiliary path, a firstgate bias network connected to the main path, and a second gate biasnetwork connected to the auxiliary path, the second gate bias networkconfigured to improve linearity of the switching function; and anantenna in communication with the RF module, the antenna configured tofacilitate transmitting and/or receiving of the RF signals.

In some embodiments, the gate bias network is configured to bias themain path in a strong inversion region and to bias the auxiliary path ina weak inversion region. In some embodiments, the circuit assembly isimplemented to switch signals to and from the antenna. In someembodiments, the circuit assembly is implemented in a series arm of amulti-pole, multi-throw switch.

According to a number of implementations, the present disclosure relatesto a circuit assembly for performing a switching function, the circuitassembly that includes a branch including a main path in parallel withan auxiliary path, both the main path and the auxiliary path having aplurality of field-effect transistors; a first gate bias networkconnected to the main path; a second gate bias network connected to afirst subset of the plurality of FETs of the auxiliary path; and a thirdgate bias network connected to a second subset of the plurality of FETsof the auxiliary path, the second gate bias network and the third gatebias network being independently configurable to improve linearity ofthe switching function.

In some embodiments, the third gate bias network is configured to biasthe second subset of the plurality of FETs using a first voltage. Insome embodiments, the second gate bias network is configured to bias thethird subset of the plurality of FETs using a second voltage differentfrom the first voltage. In some embodiments, the second gate biasnetwork is configured to bias the third subset of the plurality of FETsusing a second voltage equal to the first voltage.

In some embodiments, the third gate bias network is configured to turnoff the second subset of the plurality of FETs of the auxiliary path toimprove linearity of the switching function. In some embodiments, thesecond subset of the plurality of FETs of the auxiliary path includes agreater number of FETs than the first subset of the plurality of FETs ofthe auxiliary path. In some embodiments, the second subset of theplurality of FETs of the auxiliary path includes the same number of FETsas the first subset of the plurality of FETs of the auxiliary path.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region, the second gate bias networkis configured to bias the first subset of the plurality of FETs of theauxiliary path in a weak inversion region, and the third gate biasnetwork is configured to bias the second subset of the plurality of FETsof the auxiliary path in a weak inversion region.

In some embodiments, the second gate bias network is configured to biasthe first subset of the plurality of FETs of the auxiliary path togenerate third-order harmonics or third-order intermodulation productsthat are opposite in phase to third-order harmonics or third-orderintermodulation products generated by the main path. In someembodiments, the third gate bias network is configured to bias thesecond subset of the plurality of FETs of the auxiliary path to generatethird-order harmonics or third-order intermodulation products that areopposite in phase to third-order harmonics or third-orderintermodulation products generated by the main path.

In some embodiments, the branch is coupled between a series arm and areference potential node in a shunt configuration. In some embodiments,the second gate bias network and the third gate bias network areconfigured to reduce capacitive nonlinearity of the switching function.

According to a number of implementations, the present disclosure relatesto a circuit assembly for performing a switching function, the circuitassembly that includes a branch including a main path in series with anauxiliary path, both the main path and the auxiliary path having aplurality of field-effect transistors; a first gate bias networkconnected to the main path; a second gate bias network connected to afirst subset of the plurality of FETs of the auxiliary path; and a thirdgate bias network connected to a second subset of the plurality of FETsof the auxiliary path, the second gate bias network and the third gatebias network being independently configurable to improve linearity ofthe switching function.

In some embodiments, the third gate bias network is configured to biasthe second subset of the plurality of FETs using a first voltage. Insome embodiments, the second gate bias network is configured to bias thethird subset of the plurality of FETs using a second voltage differentfrom the first voltage. In some embodiments, the second gate biasnetwork is configured to bias the third subset of the plurality of FETsusing a second voltage equal to the first voltage.

In some embodiments, the third gate bias network is configured to turnoff the second subset of the plurality of FETs of the auxiliary path toimprove linearity of the switching function. In some embodiments, thesecond subset of the plurality of FETs of the auxiliary path includes agreater number of FETs than the first subset of the plurality of FETs ofthe auxiliary path. In some embodiments, the second subset of theplurality of FETs of the auxiliary path includes the same number of FETsas the first subset of the plurality of FETs of the auxiliary path. Insome embodiments, the first gate bias network is configured to bias themain path in a strong inversion region, the second gate bias network isconfigured to bias the first subset of the plurality of FETs of theauxiliary path in a weak inversion region, and the third gate biasnetwork is configured to bias the second subset of the plurality of FETsof the auxiliary path in a weak inversion region.

In some embodiments, the second gate bias network is configured to biasthe first subset of the plurality of FETs of the auxiliary path togenerate third-order harmonics or third-order intermodulation productsthat are opposite in phase to third-order harmonics or third-orderintermodulation products generated by the main path. In someembodiments, the third gate bias network is configured to bias thesecond subset of the plurality of FETs of the auxiliary path to generatethird-order harmonics or third-order intermodulation products that areopposite in phase to third-order harmonics or third-orderintermodulation products generated by the main path.

In some embodiments, the branch is coupled between a series arm and areference potential node in a shunt configuration. In some embodiments,the second gate bias network and the third gate bias network areconfigured to reduce capacitive nonlinearity of the switching function.

In some embodiments, the first subset of the plurality of field-effecttransistors of the auxiliary path is coupled to an input of the branch,the second subset of the plurality of field-effect transistors of theauxiliary path is coupled to an output of the branch, and the pluralityof field-effect transistors of the main path are coupled between thefirst subset and the second subset of the plurality of field-effecttransistors of the auxiliary path.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) module that includes a packaging substrateconfigured to receive a plurality of devices; and a circuit assemblymounted on the packaging substrate, the circuit assembly including abranch including a branch including a main path in parallel with anauxiliary path, both the main path and the auxiliary path having aplurality of field-effect transistors, a first gate bias networkconnected to the main path, a second gate bias network connected to afirst subset of the plurality of FETs of the auxiliary path, and a thirdgate bias network connected to a second subset of the plurality of FETsof the auxiliary path, the second gate bias network and the third gatebias network being independently configurable to improve linearity ofthe switching function.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region, the second gate bias networkis configured to bias the first subset of the plurality of FETs of theauxiliary path in a weak inversion region, and the third gate biasnetwork is configured to bias the second subset of the plurality of FETsof the auxiliary path in a weak inversion region.

According to a number of implementations, the present disclosure relatesto a wireless device that includes a transceiver configured to processradio-frequency (RF) signals; an RF module in communication with thetransceiver, the RF module including a circuit assembly including abranch including a branch including a main path in parallel with anauxiliary path, both the main path and the auxiliary path having aplurality of field-effect transistors, a first gate bias networkconnected to the main path, a second gate bias network connected to afirst subset of the plurality of FETs of the auxiliary path, and a thirdgate bias network connected to a second subset of the plurality of FETsof the auxiliary path, the second gate bias network and the third gatebias network being independently configurable to improve linearity ofthe switching function; and an antenna in communication with the RFmodule, the antenna configured to facilitate transmitting and/orreceiving of the RF signals.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region, the second gate bias networkis configured to bias the first subset of the plurality of FETs of theauxiliary path in a weak inversion region, and the third gate biasnetwork is configured to bias the second subset of the plurality of FETsof the auxiliary path in a weak inversion region. In some embodiments,the circuit assembly is implemented in a series arm of a multi-pole,multi-throw switch.

According to a number of implementations, the present disclosure relatesto a circuit assembly for performing a switching function that includesa branch including a main path in parallel with an auxiliary path, boththe main path and the auxiliary path having a plurality of field-effecttransistors; a first gate bias network connected to the main path; asecond gate bias network connected to a first subset of the plurality ofFETs of the auxiliary path; and a third gate bias network connected to asecond subset of the plurality of FETs of the auxiliary path so that thethird gate bias network switches on the auxiliary path when the mainpath is on for nonlinear cancellation, and switches off the auxiliarypath when the main path is off to enable the branch to withstand maximumvoltage swings.

The circuit assembly of claim 1 wherein the third gate bias network offthe auxiliary path responsive to performance of the main pathperformance being sufficient to achieve a targeted linearity. In someembodiments, the third gate bias network is configured to bias thesecond subset of the plurality of FETs using a first voltage. In someembodiments, the second gate bias network is configured to bias thethird subset of the plurality of FETs using a second voltage differentfrom the first voltage. In some embodiments, the second gate biasnetwork is configured to bias the third subset of the plurality of FETsusing a second voltage equal to the first voltage.

In some embodiments, the third gate bias network is configured to turnoff the second subset of the plurality of FETs of the auxiliary path toimprove linearity of the switching function. In some embodiments, thesecond subset of the plurality of FETs of the auxiliary path includes agreater number of FETs than the first subset of the plurality of FETs ofthe auxiliary path. In some embodiments, the second subset of theplurality of FETs of the auxiliary path includes the same number of FETsas the first subset of the plurality of FETs of the auxiliary path. Insome embodiments, the first gate bias network is configured to bias themain path in a strong inversion region and the second gate bias networkis configured to bias the first subset of the plurality of FETs of theauxiliary path in a weak inversion region.

In some embodiments, the second gate bias network is configured to biasthe first subset of the plurality of FETs of the auxiliary path togenerate third-order harmonics or third-order intermodulation productsthat are opposite in phase to third-order harmonics or third-orderintermodulation products generated by the main path. In someembodiments, the third gate bias network is configured to bias thesecond subset of the plurality of FETs of the auxiliary path to generatethird-order harmonics or third-order intermodulation products that areopposite in phase to third-order harmonics or third-orderintermodulation products generated by the main path.

In some embodiments, the branch is coupled between a series arm and areference potential node in a shunt configuration. In some embodiments,the second gate bias network and the third gate bias network areconfigured to reduce capacitive nonlinearity of the switching function.

In some embodiments, the second subset of the plurality of FETs of theauxiliary path are connected to an input of the branch and the firstsubset of the plurality of FETs of the auxiliary path are connected toan output of the branch. In some embodiments, the second subset of theplurality of FETs of the auxiliary path are connected to an output ofthe branch and the first subset of the plurality of FETs of theauxiliary path are connected to an input of the branch. In someembodiments, the second subset of the plurality of FETs of the auxiliarypath are connected to an input of the branch and to an output of thebranch and the first subset of the plurality of FETs of the auxiliarypath is connected in series with the second subset of the plurality ofFETs of the auxiliary path.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) module that includes a packaging substrateconfigured to receive a plurality of devices; and a circuit assemblymounted on the packaging substrate, the circuit assembly including abranch including a main path in parallel with an auxiliary path, boththe main path and the auxiliary path having a plurality of field-effecttransistors, a first gate bias network connected to the main path, asecond gate bias network connected to a first subset of the plurality ofFETs of the auxiliary path, and a third gate bias network connected to asecond subset of the plurality of FETs of the auxiliary path so that thethird gate bias network switches on the auxiliary path when the mainpath is on for nonlinear cancellation, and switches off the auxiliarypath when the main path is off to enable the branch to withstand maximumvoltage swings.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region and the second gate biasnetwork is configured to bias the first subset of the plurality of FETsof the auxiliary path in a weak inversion region.

According to a number of implementations, the present disclosure relatesto a wireless device that includes a transceiver configured to processradio-frequency (RF) signals; an RF module in communication with thetransceiver, the RF module including a circuit assembly including abranch including a main path in parallel with an auxiliary path, boththe main path and the auxiliary path having a plurality of field-effecttransistors, a first gate bias network connected to the main path, asecond gate bias network connected to a first subset of the plurality ofFETs of the auxiliary path, and a third gate bias network connected to asecond subset of the plurality of FETs of the auxiliary path so that thethird gate bias network switches on the auxiliary path when the mainpath is on for nonlinear cancellation, and switches off the auxiliarypath when the main path is off to enable the branch to withstand maximumvoltage swings; and an antenna in communication with the RF module, theantenna configured to facilitate transmitting and/or receiving of the RFsignals.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region and the second gate biasnetwork is configured to bias the first subset of the plurality of FETsof the auxiliary path in a weak inversion region.

According to a number of implementations, the present disclosure relatesto a circuit assembly for performing a switching function, the circuitassembly includes a branch including a main path in parallel with afirst auxiliary path and the main path in series with a second auxiliarypath; a first gate bias network connected to the main path; a secondgate bias network connected to the first auxiliary path; and a thirdgate bias network connected to the second auxiliary path, the secondgate bias network and the third gate bias network configured to improvelinearity of the switching function.

In some embodiments, the circuit assembly further includes a body biasnetwork coupled to the main path. In some embodiments, the body biasnetwork is further coupled to the first auxiliary path and to the secondauxiliary path.

In some embodiments, the main path comprises a plurality of field-effecttransistors. In some embodiments, the first auxiliary path comprises aplurality of field-effect transistors and the second auxiliary pathcomprises a plurality of field-effect transistors.

In some embodiments, the branch is coupled between a series arm and areference potential node in a shunt configuration. In some embodiments,the second gate bias network and the third gate bias network areconfigured to reduce capacitive nonlinearity of the switching function.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region, the second gate bias networkis configured to bias the first auxiliary path in a weak inversionregion, and the third gate bias network is configured to bias theauxiliary path in a weak inversion region. In some embodiments, thecircuit assembly further includes a bias feedback module configured toadjust a bias of the second gate bias network based at least in part ona power or a frequency of an input signal to the branch. In someembodiments, the second gate bias network is configured to bias thefirst auxiliary path to generate third-order harmonics or third-orderintermodulation products that are opposite in phase to third-orderharmonics or third-order intermodulation products generated by the mainpath.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) switching configuration that includes an inputnode configured to receive an input signal; an output node configured toprovide an output signal related to the input signal; a main-auxiliarybranch coupled between the input node and the output node, themain-auxiliary branch including a main path having a main field-effecttransistor (FET), a first auxiliary path having a first auxiliary FET,and a second auxiliary path having a second auxiliary FET, the main pathcoupled in parallel with the first auxiliary path and in series with thesecond auxiliary path; a main gate bias network configured to provide amain gate bias voltage to the main FET; a first auxiliary gate biasnetwork configured to provide a first auxiliary bias voltage to thefirst auxiliary FET such that the first auxiliary path generatesdistortions that are opposite in phase to distortions generated by themain path to reduce distortions through the main-auxiliary branch; and asecond auxiliary gate bias network configured to provide a secondauxiliary bias voltage to the second auxiliary FET such that the secondauxiliary path generates distortions that are opposite in phase todistortions generated by the main path to reduce distortions through themain-auxiliary branch.

In some embodiments, the main FET is configured to operate in a stronginversion region responsive to the main bias voltage. In someembodiments, the first auxiliary FET is configured to operate in a weakinversion region responsive to the first auxiliary bias voltage and thesecond auxiliary FET is configured to operate in a weak inversion regionresponsive to the second auxiliary bias voltage.

In some embodiments, the main gate bias voltage is greater than thefirst auxiliary gate bias voltage and the second auxiliary gate biasvoltage. In some embodiments, the main path further includes a secondmain FET. In some embodiments, the main gate bias network is furtherconfigured to provide the main gate bias voltage to the second main FET.

In some embodiments, the first auxiliary path further includes a thirdauxiliary FET. In some embodiments, the first auxiliary gate biasnetwork is further configured to provide the first auxiliary gate biasvoltage to the third auxiliary FET. In some embodiments, the RFswitching configuration further includes a third auxiliary gate biasnetwork configured to provide a third auxiliary gate bias voltage to thethird auxiliary FET. In some embodiments, the third auxiliary gate biasvoltage is different from the first auxiliary gate bias voltage and thesecond auxiliary gate bias voltage. In some embodiments, the main gatebias network is further configured to provide the main gate bias voltageto the third auxiliary FET.

In some embodiments, the RF switching configuration further includes abody bias network configured to provide a body bias voltage to the mainFET, to the first auxiliary FET, and to the second auxiliary FET. Insome embodiments, the main gate bias network is configured to providetwo static voltages to the main FET corresponding to on and off states.In some embodiments, the first auxiliary gate bias network is configuredto provide a dynamic voltage to the first auxiliary FET. In someembodiments, the first auxiliary gate bias network is configured togenerate the first auxiliary gate bias voltage responsive to a power ofthe input signal at the input node. In some embodiments, the secondauxiliary gate bias network is configured to generate the secondauxiliary gate bias voltage responsive to a frequency of the inputsignal at the input node.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) module that includes a packaging substrateconfigured to receive a plurality of devices; and a circuit assemblymounted on the packaging substrate, the circuit assembly including abranch including a main path in parallel with a first auxiliary path andthe main path in series with a second auxiliary path, a first gate biasnetwork connected to the main path, a second gate bias network connectedto the first auxiliary path, and a third gate bias network connected tothe second auxiliary path, the second gate bias network and the thirdgate bias network configured to improve linearity of the switchingfunction.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region, the second gate bias networkis configured to bias the first auxiliary path in a weak inversionregion, and the third gate bias network is configured to bias the secondauxiliary path in a weak inversion region.

According to a number of implementations, the present disclosure relatesto a wireless device that includes a transceiver configured to processradio-frequency (RF) signals; an RF module in communication with thetransceiver, the RF module including a circuit assembly including abranch including a main path in parallel with a first auxiliary path andthe main path in series with a second auxiliary path, a first gate biasnetwork connected to the main path, a second gate bias network connectedto the first auxiliary path, and a third gate bias network connected tothe second auxiliary path, the second gate bias network and the thirdgate bias network configured to improve linearity of the switchingfunction; and an antenna in communication with the RF module, theantenna configured to facilitate transmitting and/or receiving of the RFsignals.

In some embodiments, the first gate bias network is configured to biasthe main path in a strong inversion region, the second gate bias networkis configured to bias the first auxiliary path in a weak inversionregion, and the third gate bias network is configured to bias the secondauxiliary path in a weak inversion region.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features have been described herein. It is to be understoodthat not necessarily all such advantages may be achieved in accordancewith any particular embodiment. Thus, the disclosed embodiments may becarried out in a manner that achieves or optimizes one advantage orgroup of advantages as taught herein without necessarily achieving otheradvantages as may be taught or suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a FET device having an active FETimplemented on a substrate.

FIG. 2 illustrates an example of a FET device having an active FETimplemented on a substrate, the FET device including an upper layerimplemented over the substrate.

FIG. 3 illustrates an example of a FET device having an active FETimplemented on a substrate, the FET device including a lower layer andan upper layer.

FIG. 4 illustrates an example FET device implemented as an individualSOI unit

FIG. 5 illustrates a plurality of individual SOI devices implemented ona wafer.

FIG. 6A illustrates an example wafer assembly having a first wafer and asecond wafer positioned over the first wafer.

FIG. 6B illustrates an unassembled view of the first and second wafersof the example wafer assembly of FIG. 6A.

FIG. 7A illustrates a terminal representation of an SOI FET having nodesassociated with a gate, a source, a drain, a body, and a substrate.

FIG. 7B illustrates a terminal representation of an SOI FET having nodesassociated with a gate, a source, a drain, and a body.

FIGS. 8A, 8B, 8C, and 8D illustrates side sectional and plan views of anexample SOI FET device having an optional node for its substrate andvariations of the gate terminal.

FIG. 9A illustrates an SOI FET device including a biasing configurationwherein the gate and the body of the SOI FET device are respectivelybiased by a gate bias network and a body bias network.

FIG. 9B illustrates an SOI FET device including a biasing configurationwherein the gate is biased by a gate bias network and a body terminal isleft unconnected or floating.

FIGS. 10A, 10B, 10C, and 10D illustrate switching applications thatimplement one or more main-auxiliary branches having features asdescribed herein.

FIG. 11A-1 illustrates a main-auxiliary branch having a main path and anauxiliary path connected in parallel.

FIG. 11A-2 illustrates the main-auxiliary branch of FIG. 11A-1 in ashunt configuration.

FIG. 11B-1 illustrates a main-auxiliary branch having a main path and anauxiliary path connected in parallel, the auxiliary path including aplurality of FETs.

FIG. 11B-2 illustrates the main-auxiliary branch of FIG. 11B-1 in ashunt configuration.

FIG. 11C-1 illustrates a main-auxiliary branch having a main path and anauxiliary path connected in parallel, the main path including aplurality of FETs.

FIG. 11C-2 illustrates the main-auxiliary branch of FIG. 11C-1 in ashunt configuration.

FIG. 11D-1 illustrates a main-auxiliary branch having a main path and anauxiliary path connected in parallel, the main path and the auxiliarypath each including a plurality of FETs.

FIG. 11D-2 illustrates the main-auxiliary branch of FIG. 11D-1 in ashunt configuration.

FIG. 11E-1 illustrates a main-auxiliary branch having a main path and aplurality of auxiliary paths, each of the paths being connected inparallel.

FIG. 11E-2 illustrates the main-auxiliary branch of FIG. 11E-1 in ashunt configuration.

FIG. 11F-1 illustrates a main-auxiliary branch having a plurality ofmain paths and an auxiliary path, each of the paths being connected inparallel.

FIG. 11F-2 illustrates the main-auxiliary branch of FIG. 11F-1 in ashunt configuration.

FIG. 11G-1 illustrates a main-auxiliary branch having a plurality ofmain paths and a plurality of auxiliary paths, each of the paths beingconnected in parallel.

FIG. 11G-2 illustrates the main-auxiliary branch of FIG. 11G-1 in ashunt configuration.

FIG. 11H-1 illustrates a main-auxiliary branch having a main path and anauxiliary path connected in series.

FIG. 11H-2 illustrates the main-auxiliary branch of FIG. 11H-1 in ashunt configuration.

FIG. 11I-1 illustrates a main-auxiliary branch having a main path and anauxiliary path connected in series, the auxiliary path including aplurality of FETs.

FIG. 11I-2 illustrates the main-auxiliary branch of FIG. 11I-1 in ashunt configuration.

FIG. 11J-1 illustrates a main-auxiliary branch having a main path and anauxiliary path connected in series, the main path including a pluralityof FETs.

FIG. 11J-2 illustrates the main-auxiliary branch of FIG. 11J-1 in ashunt configuration.

FIG. 11K-1 illustrates a main-auxiliary branch having a main path and anauxiliary path connected in series, the main path and the auxiliary patheach including a plurality of FETs.

FIG. 11K-2 illustrates the main-auxiliary branch of FIG. 11K-1 in ashunt configuration.

FIG. 11L-1 illustrates a main-auxiliary branch having a main path and aplurality of parallel auxiliary paths, the main path connected in seriesto the plurality of parallel auxiliary paths.

FIG. 11L-2 illustrates the main-auxiliary branch of FIG. 11L-1 in ashunt configuration.

FIG. 11M-1 illustrates a main-auxiliary branch having a plurality ofparallel main paths connected in series with an auxiliary path.

FIG. 11M-2 illustrates the main-auxiliary branch of FIG. 11M-1 in ashunt configuration.

FIG. 11N-1 illustrates a main-auxiliary branch having a plurality ofparallel main paths connected in series with a plurality of parallelauxiliary paths.

FIG. 11N-2 illustrates the main-auxiliary branch of FIG. 11N-1 in ashunt configuration.

FIG. 11O-1 illustrates a main-auxiliary branch having a plurality ofparallel main paths connected in series with a first plurality ofparallel auxiliary paths and a second plurality of parallel auxiliarypaths.

FIG. 11O-2 illustrates the main-auxiliary branch of FIG. 11O-1 in ashunt configuration.

FIG. 11P-1 illustrates a main-auxiliary branch having a plurality ofparallel auxiliary paths connected in series with a first plurality ofparallel main paths and a second plurality of parallel main paths.

FIG. 11P-2 illustrates the main-auxiliary branch of FIG. 11P-1 in ashunt configuration.

FIG. 12A illustrates a main-auxiliary branch with biasing networksconfigured to selectively provide a tailored gate bias voltage to a gateof an auxiliary FET to improve performance of the main-auxiliary branch.

FIG. 12B illustrates the main-auxiliary branch of FIG. 12A without asource bias network or a drain bias network.

FIG. 12C illustrates the main-auxiliary branch of FIG. 12A without abody bias network, a source bias network, or a drain bias network.

FIG. 12D illustrates the main-auxiliary branch of FIG. 12A without abody bias network.

FIG. 12E illustrates the main-auxiliary branch of FIG. 12A without adrain bias network.

FIG. 12F illustrates the main-auxiliary branch of FIG. 12A without asource bias network.

FIGS. 13A, 13B, and 13C illustrate example embodiments of main-auxiliarydevices having an auxiliary FET or auxiliary path in parallel with amain FET or main path.

FIG. 14A illustrates an example main-auxiliary device having anauxiliary FET or auxiliary path in series with a main FET or main path.

FIG. 14B illustrates an example main-auxiliary device having a firstauxiliary FET and a second auxiliary FET in series with a main FET oneither side of the main FET.

FIG. 15A illustrates an example main-auxiliary device including twoauxiliary FETs or auxiliary paths in series with a main FET or main pathand a third auxiliary FET or auxiliary path in parallel with the mainFET.

FIG. 15B illustrates an example main-auxiliary device that includes amain FET stack or path and an auxiliary FET or path.

FIG. 15C illustrates an example main-auxiliary device that includes amain FET or path and an auxiliary FET stack or path.

FIG. 15D illustrates an example main-auxiliary device where an auxiliarypath is coupled to source and drain nodes of bottom and top FETs of amain FET stack or path.

FIG. 15E illustrates an example main-auxiliary device where a main pathis coupled to source and drain nodes of bottom and top FETs of anauxiliary FET stack or path.

FIG. 16 illustrates an example main-auxiliary device with aconfiguration similar to the device of FIG. 15A-15E where the bodies ofthe respective FETs in the device are independently biased.

FIG. 17 illustrates an example main-auxiliary device where bodies ofrespective FETs are biased using gate bias networks.

FIG. 18 illustrates an example main-auxiliary device where bodies ofauxiliary and main FETs coupled in series are biased using gate biasnetworks and a body of an auxiliary FET coupled in parallel with themain FET is independently biased using a body bias network.

FIG. 19 illustrates an example main-auxiliary device with a series ofmain-auxiliary parallel FETs or pairings coupled in series.

FIG. 20A illustrates an example main-auxiliary branch including anauxiliary FET stack and a main FET stack with FETs in individual stacksbeing capable of independent control.

FIG. 20B illustrates a variation of the main-auxiliary branch of FIG.20A wherein the gate of a FET in the auxiliary FET stack is biased usingthe gate bias network of a FET in the main FET stack.

FIG. 20C illustrates a variation of the main-auxiliary branch of FIG.20A wherein the gates of two or more of the FETs in the auxiliary FETstack are biased using the gate bias network of a FET in the main FETstack.

FIG. 20D illustrates a variation of the main-auxiliary branch of FIG.20A wherein the gates of two or more of the FETs in the auxiliary FETstack are biased using the gate bias network of two or more FETs in themain FET stack.

FIG. 20E illustrates a variation of the main-auxiliary branch of FIG.20A wherein the gates of the FETs in the auxiliary FET stack are biasedusing the gate bias network of two or more FETs in the main FET stack.

FIG. 21A illustrates an example main-auxiliary device having a firstauxiliary FET or path coupled in series with a main FET stack or paththat is in turn coupled in series with a second auxiliary FET or path,the auxiliary paths and the main path being controlled by a single gatebias network.

FIG. 21B illustrates an example main-auxiliary device having anauxiliary FET or path coupled to a main FET stack or path in parallel,the auxiliary path and the main path being controlled by a single gatebias network.

FIGS. 22A and 22B illustrate a simulation demonstrating improvedlinearity for a main-auxiliary device.

FIG. 23A illustrates an example main-auxiliary device wherein a mainpath includes a plurality of FETs biased using a main gate bias and anauxiliary path includes a plurality of FETs biased using an auxiliarygate bias independent of the main gate bias.

FIG. 23B illustrates the main-auxiliary device of FIG. 23A having afeedback loop configured to adjust the bias provided by the auxiliarygate bias.

FIG. 24A illustrates an example main-auxiliary device having a main FETstack or path and an auxiliary FET stack or path, the auxiliary pathincluding a first subset of FETs, a second subset of FETs, and a thirdsubset of FETs wherein the first and third subsets of FETs are biasedusing a first auxiliary gate bias and the second subset of FETs isbiased using a second auxiliary gate bias, the first and third subsetsof FETs controlling access to the auxiliary path.

FIG. 24B illustrates the main-auxiliary device of FIG. 24A with theremoval of the third subset of FETs in the auxiliary path.

FIG. 24C illustrates the main-auxiliary device of FIG. 24A with theremoval of the first subset of FETs in the auxiliary path.

FIG. 25 illustrates

FIG. 26A illustrates

FIG. 26B illustrates

FIG. 27A illustrates

FIG. 27B illustrates

FIGS. 28A, 28B, 28C, and 28D illustrate non-limiting examples of biasingcircuits and switches with main-auxiliary branches implemented on one ormore semiconductor die.

FIGS. 29A and 29B illustrate a plan view and a side view, respectively,of non-limiting examples of packaged modules that include biasingcircuits and switches with main-auxiliary branches.

FIG. 30 illustrates a schematic diagram of an example switchingconfiguration that can be implemented in the packaged module of FIGS.29A and 29B.

FIG. 31 illustrates an example wireless device having one or moreadvantageous features described herein.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The headings provided herein, if any, are for convenience only and donot necessarily affect the scope or meaning of the claimed invention.

INTRODUCTION

In electronics applications, field-effect transistors (FETs) can beutilized as switches. Such switches can allow, for example, routing ofradio-frequency (RF) signals in wireless devices. High performanceswitches can be important elements in a wide variety of RF systems,including cellular smartphones, WLAN front-end modules, and RF/microwavetest instruments. Linearity of the switches in these types of systemsdirectly affects the overall system performance. Silicon-on-insulator(SOI) switches have become popular due at least in part to ease ofintegration, low cost, etc. However, linearity of typical SOI switchesis not as competitive as some of its counterparts. Therefore, it wouldbe advantageous to improve the linearity of SOI switches for highperformance switching systems including wide RF applications.

Field-Effect-Transistors (FETs) are one of the most important activedevices in a typical switching circuit and its characteristics cangreatly influence circuit performance. The characteristics of the FETare largely determined by the signals/biases applied at its terminals(e.g., source, drain, gate, body or source, drain, gate, body, andsubstrate). Intelligent control of the terminal biases can improvedevice performance.

To further improve device performance, disclosed herein are active FETsthat implement a main-auxiliary branch design. Such designs include atleast two FETs, an auxiliary FET providing an auxiliary path and a mainFET providing a main path. Distortions that are generated in the mainpath, such as third-order harmonics and/or intermodulation distortions,can be reduced by distortions generated in the auxiliary path. This canbe accomplished by applying a tailored gate bias to the auxiliary pathso that the auxiliary path generates signals with distortions of asimilar magnitude but opposite in phase relative to the distortions ofthe signals in the main path. Accordingly, the overall performance inthe active FET is improved by reducing these distortions ornonlinearities. By way of example, the auxiliary path can be configured(e.g., through the physical design of the FET(s) and/or through appliedbias signals) so that cancelling harmonics are generated in theauxiliary path. In some embodiments, this reduces the overallnonlinearity of the active FET.

In some embodiments, gate, body, source, drain, and/or substrate biasvoltages can be intelligently applied to improve performance of anactive FET that includes a main-auxiliary branch. For example, theFET(s) of the main path can be biased in a strong inversion region(e.g., the voltage at the gate is much larger than the thresholdvoltage, or Vgs>>Vth) while the FET(s) of the auxiliary path can bebiased in a subthreshold or weak inversion region. Where the current andvoltage characteristics of a FET can be described as:

I=g ₁ V+g ₂ V ² +g ₃ V ³

g3 is generally positive (g3>0) if the FET is biased in a subthresholdor weak inversion region while g3 (g3<0) is negative if the FET isbiased in a strong inversion region. Accordingly, because the main pathis generally biased in the strong inversion region, the disclosedmain-auxiliary branches advantageously bias the auxiliary path in asubthreshold or weak inversion region to achieve at least partialcancellation or reduction of distortions.

As a specific example, and without intending to be limited to aparticular embodiment, where the main path is biased with a gate voltagethat is substantially above the threshold (e.g., about 3 V), the FET(s)of the main path are biased on the strong inversion region and g3 isnegative. To improve performance of the switch or other such circuitwith the main-auxiliary branch, the auxiliary path can be biased in asubthreshold or weak inversion region so that g3 is positive and itsthird harmonic is about 180 degrees out of phase from the signalsgenerated by the main path. The magnitude of the third-order harmonic isalso a function of the gate bias, and the main-auxiliary branchesdisclosed herein can be configured to tune or tailor the gate bias ofthe auxiliary path to generate a third-order harmonic of a similarmagnitude to the main path. This can result in a signal wherethird-order harmonics are substantially cancelled or reduced, therebyimproving the overall performance of the device (e.g., by reducingthird-order harmonic distortions and/or third-order intermodulationdistortions). In some embodiments, the gate voltage on the auxiliarypath is less than or equal to about 1.5 V, less than or equal to about1.2 V, less than or equal to about 0.6 V, or less than or equal to about0.5 V.

In addition, where the auxiliary path includes multiple FETs or multipleFET stacks, a plurality of gate biases can be applied to individual orgroups of FETs. This can be done to further fine-tune distortioncancellation and/or to further improve signal characteristics of themain-auxiliary branch.

As another example of improving the signal through a main-auxiliarybranch, the gate bias of the main FET can be biased in a region suchthat low R_(on) and/or C_(off) is achieved, while the gate bias of theauxiliary FET can be tuned to improve the linearity of the combinationof the auxiliary FET and the main FET. The disclosed main-auxiliarybranch configurations, and switches that employ such branchconfigurations, can realize improved performance by reducingnonlinearity, harmonics, intermodulation distortions (IMDs),cross-products, insertion losses, R_(on), C_(off), and/or anycombination of these or other similar characteristics.

The main-auxiliary branches disclosed herein provide a variety ofadvantageous features. For example, a main path, an auxiliary path,and/or a main hybrid path (e.g., a path that combines main FETs andauxiliary FETs) can be independently designed to improve performance ofthe main-auxiliary FET device. In some implementations, thecharacteristics of the auxiliary FET can be tailored to providethird-order intermodulation (IM3) with a similar magnitude and oppositephase as IM3 of the main FET to improve linearity of the main-auxiliaryFET device.

Besides tuning the gate bias signal for the auxiliary path, thecharacteristics of the auxiliary FET that can be tuned to improveperformance. For example, characteristics that can be tailored include,for example and without limitation, oxide thickness (Tox), devicegeometry, channel length, gate length, gate width, buried oxide (BOX)layer thickness, silicon thickness, channel doping (including welldoping and/or halo doping), gate work function, etc. The characteristicsof the auxiliary FET(s) can be tailored so that an applied gate bias canresult in targeted signal properties that reduce distortions generatedby the main FET(s).

Another advantageous feature is that the gate voltage of the auxiliaryFET that achieves a higher linearity is reduced relative to an SOI FETthat uses a substrate bias to achieve improved performance. This may bedue at least in part to the lower gate oxide used in some main-auxiliaryFET configurations. This lower gate oxide makes it easier to generatethe targeted voltages using a charge pump.

Another advantageous feature is that the variation of the IM3 dependenceon the gate voltage of the auxiliary FET can be better controlled due atleast in part to the lower gate oxide used relative to FET designs thatuse a substrate bias to achieve improved performance. For example, thethinner the gate oxide, the lower the variation generated by randomdopant fluctuations due to channel doping.

In some implementations, independent auxiliary FETs can be used both inseries with and in parallel with the main FET. Advantageously, thisallows different device parameters (e.g., R_(on) and C_(on), linearity)to be independently tuned, thereby improving linearity for both on andoff branches.

In some embodiments, main-auxiliary FET devices disclosed herein can beimplemented using a control terminal with up to 7 terminals (or up to 8terminals for SOI FETs) for fine-tuning of the FET characteristics toimprove switching and/or RF performance. This is in contrast to typicalFET devices that have 4 terminals (or 5 terminals for SOI FETs). Thisadditional control can improve performance of devices that implement thedisclosed main-auxiliary configurations. In this way, thecharacteristics or performance of the main FET can be controlled by thesignals applied to the terminals of the auxiliary FET.

Accordingly, disclosed herein are FET devices wherein an active signalapplied to a first FET or FET stack (the auxiliary FET or auxiliarypath) influences operation of a second FET or FET stack (the main FET ormain path) to improve performance of the second FET or FET stack. Thisimprovement can be improved linearity, for example. The disclosedmain-auxiliary FET devices can be substituted into any circuit thatutilizes a bulk FET or SOI FET. The gate bias applied to the first FETis tailored to achieve targeted signal properties. The gate bias signalsapplied to the first FET can be different from the gate bias signalsapplied to the second FET. In some embodiments, the gate signals appliedto the first FET can be dynamic and may depend, at least in part, oninput signal characteristics. In some embodiments, the gate signalsapplied to the second FET are static while the gate signals applied tothe first FET are dynamic. The gate signals applied to the first FET canbe configured so that the first FET is in a weak inversion region andthe gate signals applied to the second FET can be configured so that thesecond FET is in a strong inversion region.

In some embodiments, the auxiliary FET can be implemented as atransistor stack. Similarly, the main FET can be implemented as atransistor stack. In certain embodiments, one or both of the auxiliaryFET and/or main FET can be implemented as a transistor stack. Additionalnonlinear elements may also be combined with the disclosedmain-auxiliary FET designs for additional tuning of FET characteristics.This can be done to achieve better RF performance, for example.Accordingly, unless explicitly stated otherwise, embodiments disclosedherein that reference a main FET and/or an auxiliary FET should beunderstood to include embodiments where the main FET is implemented as atransistor stack and/or where the auxiliary FET is implemented as atransistor stack.

Disclosed herein are various examples of field-effect transistor (FET)devices having a main-auxiliary FET configuration for an active FETportion, an auxiliary FET configured to operate in a manner thatimproves the performance of a main FET relative to a configurationwithout an auxiliary FET. This is done to provide a desired operatingcondition for the active FET. In such various examples, terms such asFET device, active FET portion, and FET are sometimes usedinterchangeably, with each other, or some combination thereof.Accordingly, such interchangeable usage of terms should be understood inappropriate contexts.

FIG. 1 illustrates an example of a FET device 100 having an active FET101 implemented on a substrate 103. As described herein, the active FET101 can include a main-auxiliary FET configuration. The substrate 103can include one or more layers configured to facilitate, for example,operating functionality of the active FET, processing functionality forfabrication and support of the active FET, etc. For example, if the FETdevice 100 is implemented as a Silicon-On-Insulator (SOI) device, thesubstrate 103 can include an insulator layer such as a buried oxide(BOX) layer, an interface layer, and a handle wafer layer.

FIG. 1 further illustrates that in some embodiments, a region 105 belowthe active FET 101 can be configured to include one or more features toprovide one or more desirable operating functionalities for the activeFET 101. For the purpose of description, it will be understood thatrelative positions above and below are in the example context of theactive FET 101 being oriented above the substrate 103 as shown.Accordingly, some or all of the region 105 can be implemented within thesubstrate 103. Further, it will be understood that the region 105 may ormay not overlap with the active FET 101 when viewed from above (e.g., ina plan view).

FIG. 2 illustrates an example of a FET device 100 having an active FET101 implemented on a substrate 103. As described herein, the active FET101 can include a main-auxiliary FET configuration. The substrate 103can include one or more layers configured to facilitate, for example,operating functionality of the active FET 100, processing functionalityfor fabrication and support of the active FET 100, etc. For example, ifthe FET device 100 is implemented as a Silicon-On-Insulator (SOI)device, the substrate 103 can include an insulator layer such as aburied oxide (BOX) layer, an interface layer, and a handle wafer layer.

In the example of FIG. 2, the FET device 100 is shown to further includean upper layer 107 implemented over the substrate 103. In someembodiments, such an upper layer can include, for example, a pluralityof layers of metal routing features and dielectric layers to facilitate,for example, connectivity functionality for the active FET 100.

FIG. 2 further illustrates that in some embodiments, a region 109 abovethe active FET 101 can be configured to include one or more features toprovide one or more desirable operating functionalities for the activeFET 101. Accordingly, some or all of the region 109 can be implementedwithin the upper layer 107. Further, it will be understood that theregion 109 may or may not overlap with the active FET 101 when viewedfrom above (e.g., in a plan view).

FIG. 3 illustrates an example of a FET device 100 having an active FET101 implemented on a substrate 103, and also having an upper layer 107.In some embodiments, the substrate 103 can include a region 105 similarto the example of FIG. 1, and the upper layer 107 can include a region109 similar to the example of FIG. 2.

Examples related to some or all of the configurations of FIGS. 1-3 aredescribed herein in greater detail.

In the examples of FIGS. 1-3, the FET devices 100 are illustrated asbeing individual units (e.g., as semiconductor die). FIGS. 4-6illustrate that in some embodiments, a plurality of FET devices havingone or more features as described herein can be fabricated partially orfully in a wafer format, and then be singulated to provide suchindividual units.

For example, FIG. 4 illustrates an example FET device 100 implemented asan individual SOI unit. Such an individual SOI device can include one ormore active FETs 101 implemented over an insulator such as a BOX layer104 which is itself implemented over a handle layer such as a silicon(Si) substrate handle wafer 106. In the example of FIG. 4, the BOX layer104 and the Si substrate handle wafer 106 can collectively form thesubstrate 103 of the examples of FIGS. 1-3, with or without thecorresponding region 105.

In the example of FIG. 4, the individual SOI device 100 is shown tofurther include an upper layer 107. In some embodiments, such an upperlayer can be the upper layer 107 of FIGS. 2 and 3, with or without thecorresponding region 109.

FIG. 5 illustrates that in some embodiments, a plurality of individualSOI devices similar to the example SOI device 100 of FIG. 4 can beimplemented on a wafer 200. As shown, such a wafer can include a wafersubstrate 103 that includes a BOX layer 104 and a Si handle wafer layer106 as described in reference to FIG. 4. As described herein, one ormore active FETs can be implemented over such a wafer substrate.

In the example of FIG. 5, the SOI device 100 is shown without the upperlayer (107 in FIG. 4). It will be understood that such a layer can beformed over the wafer substrate 103, be part of a second wafer, or anycombination thereof.

FIG. 6A illustrates an example wafer assembly 204 having a first wafer200 and a second wafer 202 positioned over the first wafer 200. FIG. 6Billustrates an unassembled view of the first and second wafers 200, 202of the example of FIG. 6A.

In some embodiments, the first wafer 200 can be similar to the wafer 200of FIG. 5. Accordingly, the first wafer 200 can include a plurality ofSOI devices 100 such as the example of FIG. 4. In some embodiments, thesecond wafer 202 can be configured to provide, for example, a region(e.g., 109 in FIGS. 2 and 3) over a FET of each SOI device 100, and/orto provide temporary or permanent handling wafer functionality forprocess steps involving the first wafer 200.

Examples of SOI Implementation of FET Devices

Silicon-On-Insulator (SOI) process technology is utilized in manyswitching circuits, especially radio-frequency (RF) switching circuits,including those involving high performance, low loss, high linearityswitches. In such switching circuits, performance advantages typicallyresult from building a transistor in silicon, which sits on an insulatorsuch as an insulating buried oxide (BOX). The BOX typically sits on ahandle wafer, typically silicon, but can be glass, borosilicon glass,fused quartz, sapphire, silicon carbide, or any otherelectrically-insulating material. As described herein, themain-auxiliary transistor configurations can be implemented as an SOIdevice. These configurations may also be more broadly implemented as amain-auxiliary FET device with individual transistors having gate,source, drain, and body terminals. In some implementations, themain-auxiliary FET device can be implemented as a device with source anddrain terminals, an auxiliary gate terminal, a main gate terminal, anauxiliary body terminal, and a main body terminal. In someimplementations, substrate terminals for the auxiliary and main FETs canbe included. In certain implementations with multiple auxiliary FETsand/or main FETs, one or more of the FETs can have dedicated terminalsfor gate and/or body connections.

Typically, an SOI transistor is viewed as a 4-terminal field-effecttransistor (FET) device with gate, drain, source, and body terminals.However, an SOI FET can be represented as a 5-terminal device, with anaddition of a substrate node. Such a substrate node can be biased and/orbe coupled one or more other nodes of the transistor to, for example,improve both linearity and loss performance of the transistor. Althoughvarious examples are described in the context of RF switches, it will beunderstood that one or more features of the present disclosure can alsobe implemented in other applications involving FETs.

FIG. 7A illustrates a terminal representation of an SOI FET 100 a havingnodes associated with a gate, a source, a drain, a body, and asubstrate. FIG. 7B illustrates a terminal representation of an SOI FET100 b having nodes associated with a gate, a source, a drain, and abody. It will be understood that in some embodiments, the source and thedrain can be reversed for SOI FETS 100 a, 100 b. Such FETs 100 a, 100 bcan be used to build the main-auxiliary FET configurations disclosedherein.

FIGS. 8A and 8B illustrate side sectional and plan views of an exampleSOI FET device 100 having an optional node for its substrate 108. Thesubstrate 108 can be, for example, a silicon substrate associated with ahandle wafer 106. Although described in the context of the handle wafer106, it will be understood that the substrate 108 does not necessarilyneed to have functionality associated with a handle wafer.

An insulator layer such as a BOX layer 104 is shown to be formed overthe handle wafer 106, and a FET structure is shown to be formed based onan active silicon device 102 over the BOX layer 104. The FET structurecan be configured as an NPN or PNP device.

In the example of FIGS. 8A and 8B, terminals for the gate, source, drainand body are shown to be configured and provided so as to allowoperation of the FET. As described in greater detail herein, theseterminals can be coupled to another FET structure to form amain-auxiliary FET configuration. A substrate terminal is shown to beelectrically connected to the substrate (e.g., handle wafer) 106 throughan electrically conductive feature 108 extending through the BOX layer104. Such an electrically conductive feature can include, for example,one or more conductive vias, one or more conductive trenches, or anycombination thereof. FIGS. 8C and 8D illustrate different configurationsfor the gate terminal. FIG. 8C illustrates the gate as a “T-gate”terminal and FIG. 8D illustrates the gate as an “H-gate” terminal. Otherconfigurations and shapes of the gate terminal can also be implementedand are to be considered within the scope of this disclosure.

In some embodiments, a substrate connection can be connected to ground,for example, to avoid an electrically floating condition associated withthe substrate. Such a substrate connection for grounding typicallyincludes a seal-ring implemented at an outermost perimeter of a givendie. Further description of example implementations and associatedadvantages of the substrate connection are provided in U.S. patentapplication Ser. No. 15/085,980, entitled “SUBSTRATE BIAS FORFIELD-EFFECT TRANSISTOR DEVICES,” filed Mar. 30, 2016 (included herewithas an Appendix), which is incorporated herein by reference in itsentirety for all purposes to form part of this application.

FIG. 9A illustrates an SOI FET device 100 having features as describedherein including a biasing configuration 150 wherein the gate and thebody of the SOI FET device 100 are respectively biased by a gate biasnetwork 156 and a body bias network 154. FIG. 9B illustrates an SOI FETdevice 100 having features as described herein including a biasingconfiguration 150 wherein the gate is biased by a gate bias network 156and a body terminal is left unconnected or floating. Further details andexamples related to gate and body bias networks can be found in PCTPublication No. WO 2014/011510 entitled “CIRCUITS, DEVICES, METHODS ANDCOMBINATIONS RELATED TO SILICON-ON-INSULATOR BASED RADIO-FREQUENCYSWITCHES,” which is incorporated by reference herein in its entirety forall purposes. In some embodiments, the SOI FET device 100 of FIGS. 9Aand 9B and other devices having one or more features as described hereincan have its substrate node biased by a substrate bias network 152.

FIG. 10A illustrates that, in some embodiments, main-auxiliary branches(e.g., a main-auxiliary FET configuration) or M-A branch having one ormore features as described herein can be implemented in switchingapplications (e.g., RF switching applications). FIG. 10A illustrates anexample of an RF switching configuration 160 having an RF core 162 andan energy management (EM) core 164. Additional details concerning suchRF and EM cores can be found in the above-referenced PCT Publication No.WO 2014/011510. The example RF core 162 of FIG. 10A is shown as asingle-pole-double-throw (SPDT) configuration in which series arms oftransistors 100 a, 100 b are arranged between a pole and first andsecond throws, respectively. Throw 1 is coupled to a main-auxiliarybranch 100 a and throw 2 is coupled to a FET device 100 b. Themain-auxiliary branch 100 a includes one or more active devices in amain path or a main hybrid path and one or more active devices in anauxiliary path, as described in greater detail herein. Nodes associatedwith the first and second throws are shown to be coupled to a referencepotential node (e.g., ground) through their respective shunt arms ofFETs 100 c, 100 d. It will be understood that other switchingconfigurations can also be implemented with a main-auxiliary branchconfiguration having one or more of the features described herein. Forexample, a single pole single throw (SPST) switch can be implemented, asingle pole multiple throw (SPNT) switch can be implemented, a multiplepole single throw (MPST) switch can be implemented, a multiple polemultiple throw (MPNT) can be implemented, and the like.

FIGS. 10A-10D illustrate that one, some, or all of the active devices100 a-100 d can be implemented as a stack of FET devices in amain-auxiliary branch configuration, examples of which are describedherein. The main-auxiliary branches (M-A branches) can be implemented toimprove signal characteristics in switching applications. For exampleand without limitation, the main-auxiliary branches 100 a, 100 b, 100 c,and/or 100 d can be configured to improve linearity, reduce harmonics,reduce intermodulation distortions, reduce cross products, reduceinsertion losses, achieve low R_(on), achieve low C_(on), and/or reducegate bias voltages. Each of the main-auxiliary branches 100 c and 100 dare implemented in a shunt configuration.

For the purpose of description, each FET in a main-auxiliary branch canbe referred to as a FET, the stack of FETs can be collectively referredto as a FET, or some combination thereof can also be referred to as aFET. Furthermore, each FET in the stack can be biased with a separategate, body, and/or substrate bias network; a plurality of the FETs inthe stack can be biased with a common gate, body, and/or substrate biasnetwork; or any combination thereof.

Other switching configurations involving a single pole (SP) can beimplemented utilizing one or more of the main-auxiliary configurationswith one or more features as described herein. Thus, it will beunderstood that a switch having a SPNT can be implemented utilizing oneor more of the main-auxiliary configurations as described herein, wherethe quantity N is a positive integer. Furthermore, it will be understoodthat a switch having multiple poles and multiple throws (MPNT) can beimplemented utilizing one or more of the main-auxiliary configurationsas described herein, where the quantities M and N are independentpositive integers. For example, in many applications switchingconfigurations having a plurality of poles and a plurality of throws canprovide increased flexibility in how RF signals can be routedtherethrough.

It is noted that in various switching configuration examples describedherein, switchable shunt paths are not shown for simplified views of theswitching configurations. Accordingly, it will be understood that someor all of switchable paths in such switching configurations may or maynot have associated with them switchable shunt paths (e.g., similar tothe example of FIGS. 10A-10D).

Example Main-Auxiliary Branch Configurations

FIGS. 11A-1 through 11P-2 illustrate a variety of example main-auxiliarybranch configurations. The main-auxiliary branch configurations can beconfigured to act as a switch. Similarly, the main-auxiliary branchconfigurations can be configured as a shunt. In certain implementations,such as when the configuration acts as a switch or is part of a seriesarm in a switch circuit, the main-auxiliary branch configurations caninclude a main path and an auxiliary path between an input node and anoutput node. In various implementations, such as in a shuntconfiguration, the main-auxiliary branch configurations can beconfigured to provide a switchable path to a reference potential node(e.g., ground). This can be done to provide a shunt path in switch, suchas the configurations illustrated in FIGS. 10C and 10D. Accordingly, ashunt configuration, as described herein, includes a switchable path toa reference potential node that couples to a signal line, the signalline providing a path between an input node and an output node. Theshunt configuration has a first node coupled to the signal line betweenthe input node and the output node and a second node coupled to areference potential node. The shunt configuration can be configured sothat the main-auxiliary branch reduces capacitive nonlinearity of theswitching function. In some embodiments, the main path and the auxiliarypath can be segmented with nodes between the segments being connected toone another, thereby forming a main hybrid path, or a path that includesmain and auxiliary active devices (e.g., FETs).

FIG. 11A-1 illustrates a main-auxiliary branch 1100 a having a main path1140 and an auxiliary path 1145 connected in parallel. The main path1140 includes a FET 1142 and the auxiliary path 1145 includes a FET1147. FIG. 11A-2 illustrates the main-auxiliary branch 1100 a of FIG.11A-1 in a shunt configuration.

FIG. 11B-1 illustrates a main-auxiliary branch 1100 b having a main path1140 and an auxiliary path 1145 connected in parallel. The main path1140 includes a FET 1142 and the auxiliary path 1145 includes aplurality of FETs 1147. FIG. 11B-2 illustrates the main-auxiliary branch1100 b of FIG. 11B-1 in a shunt configuration.

FIG. 11C-1 illustrates a main-auxiliary branch 1100 c having a main path1140 and an auxiliary path 1145 connected in parallel. The main path1140 includes a plurality of FETs 1142 and the auxiliary path 1145includes a FET 1147. FIG. 11C-2 illustrates the main-auxiliary branch1100 c of FIG. 11C-1 in a shunt configuration.

FIG. 11D-1 illustrates a main-auxiliary branch 1100 d having a main path1140 and an auxiliary path 1145 connected in parallel. The main path1140 includes a plurality of FETs 1142 and the auxiliary path 1145includes a plurality of FETs 1147. The number of FETs in the main path1140 can differ from the number of FETs in the auxiliary path 1145. FIG.11D-2 illustrates the main-auxiliary branch 1100 d of FIG. 11D-1 in ashunt configuration.

FIG. 11E-1 illustrates a main-auxiliary branch 1100 e having a main path1140 and a plurality of auxiliary paths 1145 a, 1145 b, each of thepaths being connected in parallel. The main path 1140 includes aplurality of FETs 1142 and the auxiliary paths 1145 a, 1145 b include aplurality of FETs 1147 a, 1147 b. However, it is to be understood thatthe main path 1140 and/or individual auxiliary paths 1145 a, 1145 b caninclude a single FET or a plurality of FETs. In addition, the number ofFETs in individual paths can be the same or different from one another.FIG. 11E-2 illustrates the main-auxiliary branch 1100 e of FIG. 11E-1 ina shunt configuration.

FIG. 11F-1 illustrates a main-auxiliary branch 1100 f having a pluralityof main paths 1140 a, 1140 b and an auxiliary path 1145, each of thepaths being connected in parallel. The main paths 1140 a, 1140 b includea plurality of FETs 1142 a, 1142 b and the auxiliary path 1145 includesa plurality of FETs 1147. However, it is to be understood thatindividual main paths 1140 and/or the auxiliary path 1145 can include asingle FET or a plurality of FETs. In addition, the number of FETs inindividual paths can be the same or different from one another. FIG.11F-2 illustrates the main-auxiliary branch 1100 f of FIG. 11F-1 in ashunt configuration.

FIG. 11G-1 illustrates a main-auxiliary branch 1100 g having a pluralityof main paths 1140 a, 1140 b and a plurality of auxiliary paths 1145 a,1145 b, each of the paths being connected in parallel. The main paths1140 a, 1140 b include a plurality of FETs 1142 a, 1142 b and theauxiliary paths 1145 a, 1145 b include a plurality of FETs 1147 a, 1147b. However, it is to be understood that individual main paths 1140and/or individual auxiliary paths 1145 a, 1145 b can include a singleFET or a plurality of FETs. In addition, the number of FETs inindividual paths can be the same or different from one another. FIG.11G-2 illustrates the main-auxiliary branch 1100 g of FIG. 11G-1 in ashunt configuration.

FIG. 11H-1 illustrates a main-auxiliary branch 1100 h having a main path1140 and an auxiliary path 1145 connected in series. The main path 1140includes a FET 1142 and the auxiliary path 1145 includes a FET 1147. Itis to be understood that the order of the main path 1140 and theauxiliary path 1145 can be reversed so that the main path 1140 ispositioned between the input node and the auxiliary path 1145 and theauxiliary path 1145 is positioned between the output node and the mainpath 1140. FIG. 11H-2 illustrates the main-auxiliary branch 1100 h ofFIG. 11H-1 in a shunt configuration.

FIG. 11I-1 illustrates a main-auxiliary branch 1100 i having a main path1140 and an auxiliary path 1145 connected in series. The main path 1140includes a FET 1142 and the auxiliary path 1145 includes a plurality ofFETs 1147. It is to be understood that the order of the main path 1140and the auxiliary path 1145 can be reversed so that the main path 1140is positioned between the input node and the auxiliary path 1145 and theauxiliary path 1145 is positioned between the output node and the mainpath 1140. FIG. 11I-2 illustrates the main-auxiliary branch 1100 i ofFIG. 11I-1 in a shunt configuration.

FIG. 11J-1 illustrates a main-auxiliary branch 1100 j having a main path1140 and an auxiliary path 1145 connected in series. The main path 1140includes a plurality of FETs 1142 and the auxiliary path 1145 includes aFET 1147. It is to be understood that the order of the main path 1140and the auxiliary path 1145 can be reversed so that the main path 1140is positioned between the input node and the auxiliary path 1145 and theauxiliary path 1145 is positioned between the output node and the mainpath 1140. FIG. 11J-2 illustrates the main-auxiliary branch 1100 j ofFIG. 11J-1 in a shunt configuration.

FIG. 11K-1 illustrates a main-auxiliary branch 1100 k having a main path1140 and an auxiliary path 1145 connected in series. The main path 1140includes a plurality of FETs 1142 and the auxiliary path 1145 includes aplurality of FETs 1147. The number of FETs in the main path 1140 candiffer from the number of FETs in the auxiliary path 1145. It is to beunderstood that the order of the main path 1140 and the auxiliary path1145 can be reversed so that the main path 1140 is positioned betweenthe input node and the auxiliary path 1145 and the auxiliary path 1145is positioned between the output node and the main path 1140. FIG. 11K-2illustrates the main-auxiliary branch 1100 k of FIG. 11K-1 in a shuntconfiguration.

FIG. 11L-1 illustrates a main-auxiliary branch 11001 having a main path1140 and a plurality of parallel auxiliary paths 1145 a, 1145 b, themain path 1140 connected in series to the plurality of parallelauxiliary paths 1145 a, 1145 b. The main path 1140 includes a pluralityof FETs 1142 and the plurality of auxiliary paths 1145 a, 1145 b eachincludes a plurality of FETs 1147 a, 1147 b. However, it is to beunderstood that the main path 1140 and/or individual auxiliary paths1145 a, 1145 b can include a single FET or a plurality of FETs. Inaddition, the number of FETs in individual paths can be the same ordifferent from one another. It is to be understood that the order of themain path 1140 and the plurality of parallel auxiliary paths 1145 a,1145 b can be reversed so that the main path 1140 is positioned betweenthe input node and the plurality of parallel auxiliary paths 1145 a,1145 b and the plurality of parallel auxiliary paths 1145 a, 1145 b ispositioned between the output node and the main path 1140. FIG. 11L-2illustrates the main-auxiliary branch 11001 of FIG. 11L-1 in a shuntconfiguration.

FIG. 11M-1 illustrates a main-auxiliary branch 1100 m having a pluralityof parallel main paths 1140 a, 1140 b connected in series with anauxiliary path 1145. The plurality of main paths 1140 a, 1140 b eachinclude a plurality of FETs 1142 a, 1142 b and the auxiliary path 1145includes a plurality of FETs 1147. However, it is to be understood thatindividual main paths 1140 a, 1140 b and/or the auxiliary path 1145 caninclude a single FET or a plurality of FETs. In addition, the number ofFETs in individual paths can be the same or different from one another.It is to be understood that the order of the plurality of parallel mainpaths 1140 a, 1140 b and the auxiliary path 1145 can be reversed so thatthe plurality of parallel main paths 1140 a, 1104 b is positionedbetween the input node and the auxiliary path 1145 and the auxiliarypath 1145 is positioned between the output node and the plurality ofparallel main paths 1140 a, 1140 b. FIG. 11M-2 illustrates themain-auxiliary branch 1100 m of FIG. 11M-1 in a shunt configuration.

FIG. 11N-1 illustrates a main-auxiliary branch 1100 n having a pluralityof parallel main paths 1140 a, 1140 b connected in series with aplurality of parallel auxiliary paths 1145 a, 1145 b. The plurality ofmain paths 1140 a, 1140 b each include a plurality of FETs 1142 a, 1142b and the plurality of auxiliary paths 1145 a, 1145 b each include aplurality of FETs 1147 a, 1147 b. However, it is to be understood thatindividual main paths 1140 a, 1140 b and/or individual auxiliary paths1145 a, 1145 b can include a single FET or a plurality of FETs. Inaddition, the number of FETs in individual paths can be the same ordifferent from one another. It is to be understood that the order of theplurality of parallel main paths 1140 a, 1140 b and the plurality ofparallel auxiliary paths 1145 a, 1145 b can be reversed so that theplurality of parallel main paths 1140 a, 1104 b is positioned betweenthe input node and the plurality of parallel auxiliary paths 1145 a,1145 b and the plurality of parallel auxiliary paths 1145 a, 1145 b ispositioned between the output node and the plurality of parallel mainpaths 1140 a, 1140 b. FIG. 11N-2 illustrates the main-auxiliary branch1100 n of FIG. 11N-1 in a shunt configuration.

FIG. 11O-1 illustrates a main-auxiliary branch 1100 o having a pluralityof parallel main paths 1140 a, 1140 b connected in series with a firstplurality of parallel auxiliary paths 1145 a and a second plurality ofparallel auxiliary paths 1145 b, the plurality of parallel main paths1140 a, 1140 b positioned between the first plurality of parallelauxiliary paths 1145 a and the second plurality of parallel auxiliarypaths 1145 b. The plurality of main paths 1140 a, 1140 b each include aplurality of FETs 1142 a, 1142 b and the plurality of auxiliary paths1145 a, 1145 b each include a plurality of FETs 1147 a, 1147 b. However,it is to be understood that individual main paths 1140 a, 1140 b and/orindividual auxiliary paths 1145 a, 1145 b can include a single FET or aplurality of FETs. In addition, the number of FETs in individual pathscan be the same or different from one another. FIG. 11O-2 illustratesthe main-auxiliary branch 11000 of FIG. 11O-1 in a shunt configuration.

FIG. 11P-1 illustrates a main-auxiliary branch 1100 p having a pluralityof parallel auxiliary paths 1145 a, 1145 b connected in series with afirst plurality of parallel main paths 1140 a and a second plurality ofparallel main paths 1140 b, the plurality of parallel auxiliary paths1145 a, 1145 b positioned between the first plurality of parallel mainpaths 1140 a and the second plurality of parallel main paths 1140 b. Theplurality of main paths 1140 a, 1140 b each include a plurality of FETs1142 a, 1142 b and the plurality of auxiliary paths 1145 a, 1145 b eachinclude a plurality of FETs 1147 a, 1147 b. However, it is to beunderstood that individual main paths 1140 a, 1140 b and/or individualauxiliary paths 1145 a, 1145 b can include a single FET or a pluralityof FETs. In addition, the number of FETs in individual paths can be thesame or different from one another. FIG. 11P-2 illustrates themain-auxiliary branch 1100 p of FIG. 11P-1 in a shunt configuration.

FIG. 12A illustrates a main-auxiliary branch 1200 with biasing networks1250 configured to selectively provide a tailored gate bias to a gate ofan auxiliary FET to improve performance of the main-auxiliary branch1200. The main-auxiliary branch 1200 includes an auxiliary path havingone or more FETs that is configured to influence operation of a mainpath having one or more FETs, the auxiliary path being coupled to themain path in parallel and/or in series. The main-auxiliary branch 1200is configured to receive a signal at an input terminal (e.g., a sourceor drain terminal) and to output a signal at an output terminal (e.g., adrain or source terminal).

A gate bias network 1256 is coupled to the main-auxiliary branch 1200 toselectively apply gate bias signals to the auxiliary FET(s) and the mainFET(s) of the main-auxiliary branch 1200. The gate bias network 1256 canbe similar to gate bias networks described herein. The gate bias network1256 can include one or more gate bias networks. In some embodiments,individual auxiliary FETs in the main-auxiliary branch 1200 can becoupled to a dedicated gate bias network. In certain embodiments, aplurality of auxiliary FETs in the main-auxiliary branch 1200 can becoupled to a single gate bias network. In various embodiments, aplurality of auxiliary gate bias networks can be included in the gatebias network 1256 where individual auxiliary gate bias networks arecoupled to one or more auxiliary FETs in the main-auxiliary branch 1200.Similarly, in some embodiments, individual main FETs in themain-auxiliary branch 1200 can be coupled to a dedicated gate biasnetwork. In certain embodiments, a plurality of main FETs in themain-auxiliary branch 1200 can be coupled to a single gate bias network.In various embodiments, a plurality of main gate bias networks can beincluded in the gate bias network 1256 where individual main gate biasnetworks are coupled to one or more main FETs in the main-auxiliarybranch 1200.

A body bias network 1254 is coupled to the main-auxiliary branch 1200 toselectively apply body bias signals to the auxiliary FET(s) and/or mainFET(s) of the main-auxiliary branch 1200. The body bias network 1254 canbe similar to the body bias networks described herein. The body biasnetwork 1254 can include one or more body bias networks. In someimplementations, such as the example embodiment of FIG. 12D, the bodybias network 1254 is not included and the bodies of the respectiveauxiliary FET(s) and main FET(s) are biased using the gate bias network1256 or the bodies of the respective auxiliary FET(s) and main FET(s)are left unconnected or floating.

In some embodiments, individual auxiliary FETs in the main-auxiliarybranch 1200 can be coupled to a dedicated body bias network. In certainembodiments, a plurality of auxiliary FETs in the main-auxiliary branch1200 can be coupled to a single body bias network. In variousembodiments, a plurality of auxiliary body bias networks can be includedin the body bias network 1254 where individual auxiliary body biasnetworks are coupled to one or more auxiliary FETs in the main-auxiliarybranch 1200. Similarly, in some embodiments, individual main FETs in themain-auxiliary branch 1200 can be coupled to a dedicated body biasnetwork. In certain embodiments, a plurality of main FETs in themain-auxiliary branch 1200 can be coupled to a single body bias network.In various embodiments, a plurality of main body bias networks can beincluded in the body bias network 1254 where individual main body biasnetworks are coupled to one or more main FETs in the main-auxiliarybranch 1200.

A source bias network 1251 can be coupled to the main-auxiliary branch1200 to selectively apply source bias signals to the main-auxiliarybranch 1200. The source bias network 1251 can be coupled between theinput node and the main-auxiliary branch 1200. Similarly, a drain biasnetwork 1257 can be coupled to the main-auxiliary branch 1200 toselectively apply drain bias signals to the main-auxiliary branch 1200.The drain bias network 1257 can be coupled between the output node andthe main-auxiliary branch 1200.

A substrate bias network 1252 can be coupled to the main-auxiliarybranch 1200 to selectively apply substrate bias signals to the auxiliaryFET(s) and/or main FET(s) of the main-auxiliary branch 1200. Thesubstrate bias network 1252 can be similar to the substrate biasnetworks described herein. The substrate bias network 1252 can includeone or more substrate bias networks. In some implementations, thesubstrate bias network 1252 is not included. In such implementations,the substrates of the respective auxiliary FET(s) and main FET(s) can beleft floating or coupled to another bias network such as the body biasnetwork 1254 or the gate bias network 1256. In some embodiments, theFETs in the main-auxiliary branch 1200 do not include SOI FETs and/or donot include substrate terminals so the substrate bias network 1252 canbe omitted.

FIG. 12B illustrates the main-auxiliary branch 1200 without a sourcebias network or a drain bias network. FIG. 12C illustrates themain-auxiliary branch 1200 without a body bias network, a source biasnetwork, or a drain bias network. In such embodiments, the bodyterminals of the FETs can be left floating and/or can be coupled to thegate bias network 1256. FIG. 12D illustrates the main-auxiliary branch1200 without a body bias network. In such embodiments, the bodyterminals of the FETs can be left floating and/or can be coupled to thegate bias network 1256. FIG. 12E illustrates the main-auxiliary branch1200 without a drain bias network. FIG. 12F illustrates themain-auxiliary branch 1200 without a source bias network.

The main-auxiliary branches 1200 described herein with reference toFIGS. 12A-12F can be configured to provide improved device performancerelative to switches that use FETs without an auxiliary FET or path.Gate, body, source, drain, and/or substrate bias voltages can beintelligently applied to the main-auxiliary branch 1200 to improveperformance of the active FET in switching applications. For example,the gate bias of the main FET can be biased in a region such that lowR_(on) and/or C_(off) is achieved, while the gate bias of the auxiliaryFET can be tuned to improve the linearity of the combination of theauxiliary and main FETs. In certain implementations, the gate bias ofthe auxiliary FET can be tailored such that harmonics generated by theauxiliary FET are in opposite phase as the harmonics generated by themain FET, thereby improving linearity of the active FET circuit.

The main-auxiliary branch 1200 can be implemented in switching circuits(e.g., in a series arm and/or in a shunt configuration). Otherapplications may also use the disclosed main-auxiliary configurationswhere linearity of signal through a transistor is important.

FIGS. 13A through 24C illustrate various example embodiments ofmain-auxiliary devices or branches. Although these example embodimentsare illustrated and described as being between an input node and anoutput node, it should be understood that the example embodiments can beimplemented in a shunt configuration, providing a switchable path to areference potential node, as described herein.

FIG. 13A illustrates an example embodiment of a main-auxiliary device1300 having an auxiliary FET or auxiliary path 1345 in parallel with amain FET or main path 1340. The auxiliary FET and the main FET share thesame source and drain connections. An input signal is received at asignal input port and, if the device 1300 is activated, the device 1300outputs a signal at an output signal port.

A gate bias network 1 1356 a can be coupled to the main FET and a gatebias network 2 1356 b can be coupled to the auxiliary FET. The gate biasnetworks 1356 a, 1356 b can be operated independently to improveperformance of the device. The independent gate bias networks 1356 a,1356 b allow for independent control of the auxiliary FET and the mainFET to improve performance of the device by, for example, reducingnonlinearity. This also allows tuning of the characteristics of theauxiliary FET to improve performance of the device. For example, thegate bias voltage applied to the auxiliary FET can be tailored to reducenonlinearities in the signal through the device. In some embodiments,the characteristics of the auxiliary FET can be tailored to reduceR_(on) and/or C_(off) of the device. In some embodiments, thecharacteristics of the auxiliary FET can be tailored to reduceharmonics, intermodulation distortion, insertion losses, and/or crossproducts.

In some embodiments, the gate bias network 1 1356 a provides a firstgate bias voltage to the main path 1340 and the gate bias network 2 1356b provides a second gate bias voltage to the auxiliary path, the firstgate bias voltage different from the second gate bias voltage. Incertain implementations, the first gate bias voltage can be configuredso that the main path 1340 operates in a strong inversion region and thesecond gate bias voltage can be configured so that the auxiliary path1345 operates in a subthreshold or weak inversion region. The first gatebias voltage can be static or dynamic. The second gate bias voltage canbe static or dynamic. In some embodiments, the second gate bias voltagedepends at least in part on characteristics of the input signal. Thecharacteristics of the input signal can include, for example, inputpower, frequency, and the like.

A body bias network 1354 is coupled to a body terminal of both the mainFET and the auxiliary FET. In some embodiments, the body terminals canbe coupled to separate body bias networks. The body bias network 1354 iscoupled to the respective body nodes of the auxiliary FET and main FETof the device 1300.

The device 1300 can include a source bias network 1351 coupled at theinput node. The source bias network 1351 can be configured to improveperformance of the main-auxiliary device 1300. The device 1300 caninclude a drain bias network 1357 coupled at the output node. The drainbias network 1357 can be configured to improve performance of themain-auxiliary device 1300. The source bias network 1351 and/or thedrain bias network 1357 can be omitted, in some embodiments.Furthermore, for each example embodiment illustrated in FIGS. 13Athrough 24C, the illustrated source bias networks (referenced withcallouts NN51 where NN corresponds to the figure number) and/or drainbias networks (referenced with callouts NN57 where NN corresponds to thefigure number) may be included or omitted.

FIG. 13B illustrates the main-auxiliary device 1300 wherein the bodybias network 1354 is configured to allow application of a DC controlvoltage (V_control) to the respective body nodes. FIG. 13C illustratesthe main-auxiliary device 1300 wherein the control voltage is appliedthrough an electrical component 1353 (e.g., a resistor, a diode, acombination of a resistor and diode, or the like). Other configurationsare possible for the body bias network 1354 including, for example andwithout limitation, phase-matching circuits, capacitances, diodes, andthe like.

It is to be understood that although the main path 1340 and theauxiliary path 1345 are each illustrated using a single FET, the mainpath 1340 can include a plurality of FETs or active devices, theauxiliary path 1345 can include a plurality of FETs or active devices,or each of the main path 1340 and the auxiliary path 1345 can include aplurality of FETs or active devices. In addition, the main path 1340and/or the auxiliary path 1345 can include gated diodes, capacitors,and/or FETs as active devices. Furthermore, for each example embodimentillustrated in FIGS. 13A through 24C, unless explicitly statedotherwise, where an individual FET is illustrated, it is to beunderstood that a plurality of active devices or a stack of activedevices can be implemented.

FIG. 14A illustrates an example main-auxiliary device 1400 having anauxiliary FET or auxiliary path 1445 in series with a main FET or mainpath 1440. In this configuration, the auxiliary FET 1445 can still beused to affect and improve performance of the main FET 1440, resultingin improved performance of the device 1400 relative to a device withouta main-auxiliary configuration. The main FET 1440 has a source nodecoupled to an input signal node, a drain node coupled to a source nodeof the auxiliary FET 1445 and the auxiliary FET 1445 has a drain nodecoupled to an output signal port. In some embodiments, the source anddrain nodes of the auxiliary FET 1445 and the main FET 1440 can bereversed.

As in FIG. 13A, the device 1400 includes gate bias networks 1456 a, 1456b that allow for independent control of the auxiliary FET 1445 and themain FET 1440. Also, the body bias network 1454 can be used to provide abias voltage to the bodies of the auxiliary FET 1445 and the main FET1440, but independent body bias networks may also be utilized.

FIG. 14B illustrates a variation on the device 1400 described withreference to FIG. 14A. The device 1400 can include a second auxiliaryFET 1445 b in addition to the first auxiliary FET 1445 a, the twoauxiliary FETs 1445 a, 1445 b in series with the main FET 1440 on eitherside of the main FET. The device is controlled using 2 independent gatebias networks where the auxiliary FETs 1445 a, 1445 b are controlled byindividual or joint gate bias networks 1456 b, 1456 c (e.g., the gatebias networks 1456 b, 1456 c can be independent, tied together, or itcan be a single bias network) and the main FET 1440 is controlled by thegate bias network 1 1456 a. Gate bias signals to the respectiveauxiliary FETs 1445 a, 1445 b can be tailored to achieved targetedperformance from the main-auxiliary device 1400. Furthermore, the gatebias network 2 1456 b provides a gate bias signal to the first auxiliaryFET 1445 a that can be tuned independently of the gate bias signalprovided by the gate bias network 2′ 1456 c to the second auxiliary FET1445 b to achieve targeted performance characteristics.

FIG. 15A illustrates an example main-auxiliary device 1500 including twoauxiliary FETs or auxiliary paths 1545 a, 1545 b in series with a mainFET or main path 1540 and a third auxiliary FET or auxiliary path 1545 cin parallel with the main FET 1540. The device 1500 can include two (ormore) auxiliary FETs either in parallel or in series with the main FETwith independent gate biases to achieve improved overall performance.With independent auxiliary FETs both in series with and in parallel withthe main FET, the R_(on)/C_(off) linearity can be independently tuned toimprove linearity for both ON and OFF branches. The device 1500 isconfigured as a combination of the device 1300, described herein withreference to FIGS. 13A-13C, and the device 1400, described herein withreference to FIGS. 14A and 14B. As in those devices, the device 1500 canbe independently controlled using gate bias networks 1556 a-1556 d. Insome embodiments, the auxiliary gate bias networks 1556 b and 1556 c canbe tied together or can be a common bias network. The bodies of theauxiliary FETs and the main FET can be shared with a common body biasnetwork 1554. In some embodiments, one or more of the bodies of theauxiliary FETs and/or the main FET is independent and controlledindependently or with the common body bias network 1554.

FIG. 15B illustrates an example main-auxiliary device 1500 that includesa main FET stack or path 1540 and an auxiliary FET or path 1545. Themain FET stack 1540 includes a plurality of main FETs connected inseries. The auxiliary FET 1545 is coupled in parallel with one or moreof the main FETs. In some embodiments, as illustrated in FIG. 15C, theauxiliary and main configurations are reversed, the device 1500including an auxiliary FET stack 1540 and a main FET 1540 in parallelwith one or more of the FETs in the auxiliary FET stack 1545. FIG. 15Dillustrates the main-auxiliary device 1500 where the auxiliary path 1545is coupled to the source and drain nodes of the bottom and top FETs ofthe main stack 1540. Similarly, FIG. 15E illustrates the main-auxiliarydevice 1500 where the main path 1540 is coupled to the source and drainnodes of the bottom and top FETs of the auxiliary stack 1545.

The device 1500 illustrates that both the auxiliary FET and the main FETcan be 1-stack or multi-stack devices. The device can have the samesource/drain node for each stack or can connect source/drain nodes afterN stacks (not shown). The source/drain node of the auxiliary FET can bethe same as the main FET or in between (e.g., coupled in parallel withone or more FETs within the stack). The number of FETs in the auxiliaryand/or main stack can be different from one another.

As with the other devices described herein, the body and/or substrate ofthe main-auxiliary device 1500 can be shared between the active devicesof the auxiliary and main paths. This allows a single body bias networkto be used to bias the bodies of the respective devices. For example,auxiliary FETs and main FETs of the respective paths can have sharedbodies so that a bias voltage applied to one body is applied to theother bodies. However, other configurations allow for auxiliary FETs andmain FETs to have independent bodies and/or substrates. In suchconfigurations, the independent bodies can be independently biased orthey can be biased using a common body bias network. Accordingly, themain-auxiliary devices 1500 disclosed herein can include a body that isshared or not shared.

FIG. 16 illustrates an example main-auxiliary device 1600 with aconfiguration similar to the device 1500 described herein with referenceto FIGS. 15A-15E. The device 1600 illustrates a configuration where thebodies of the respective FETs in the device 1600 are independentlybiased using body bias networks 1654 a-1654 d. In addition, the device1600 includes a main hybrid path 1640 that includes one or moreauxiliary FETs in series with one or more main FETs, the main hybridpath being connected in parallel with an auxiliary path 1645. Forexample, the top or the bottom active device in the main hybrid path1640 can be a main FET and the middle FET or FET stack can be anauxiliary device that is coupled in parallel with the auxiliary path1645.

FIG. 17 illustrates an example main-auxiliary device 1700 with aconfiguration similar to the device 1600 described herein with referenceto FIG. 16. However, the device 1700 illustrates a configuration wherethe bodies of the respective FETs are biased using the gate biasnetworks 1756 a-1756 d. The device 1700 includes a coupling circuit foreach auxiliary FET and main FET in the device, wherein the couplingcircuit couples the respective body nodes to the gate nodes. Thecoupling circuit can include a diode between the body node and the gatenode. Such a diode can be implemented to, for example, providevoltage-dependent couplings. In some embodiments, a given diode can bereversed from the configuration as shown as needed or desired.

FIG. 18 illustrates an example main-auxiliary device 1800 with aconfiguration similar to the device 1600 described herein with referenceto FIG. 16. However, the device 1800 illustrates a configuration wherethe bodies of the auxiliary and main FETs that are coupled together inseries are biased using the gate bias networks 1856 a-1856 c and thebody of the auxiliary FET coupled in parallel with the main hybrid path1840 is independently biased using body bias network 1854. In someembodiments, it is the main hybrid path 1840 that is independentlycontrolled by the body bias network 1854 and each auxiliary FET has abody node electrically coupled to its gate node to be controlled by theassociated gate bias networks 1856 b-1856 d. In some embodiments, one ormore body terminals of auxiliary FETs and/or main FETs can be coupled toa gate bias network and one or more body terminals of auxiliary FETsand/or main FETs can be coupled to individual body bias networks or acommon body bias network.

FIG. 19 illustrates an example main-auxiliary device 1900 with a seriesof main-auxiliary parallel FETs coupled in series. Each main-auxiliaryparallel FET or main-auxiliary pairing includes an auxiliary FET and amain FET connected in parallel, sharing source and drain nodes. Thesemain-auxiliary parallel FETs also share a body or have body nodes thatare coupled together. As illustrated, these body nodes are electricallycoupled to the gate bias networks 1956 d-1956 f of the respectiveauxiliary FETs using a coupling circuit with a diode, but it is to beunderstood that a common or individualized body bias network can beutilized. The main path 1940 and the auxiliary path 1945 form asegmented main-auxiliary branch 1900 wherein a signal through the branch1900 is divided at each main-auxiliary pairing and combined at a nodebetween the pairings.

The main-auxiliary parallel FETs are coupled together in series to formthe main-auxiliary device 1900. The respective auxiliary FETs 1945 andmain FETs 1940 can be independently controlled using gate bias networks1956 a-1956 f. However, it is to be understood that two or moreauxiliary FETs may be controlled using a common auxiliary gate biasnetwork. Similarly, it is to be understood that two or more main FETsmay be controlled using a common main gate bias network. Although threemain-auxiliary parallel FETs are illustrated, it is to be understoodthat the device 1900 can include at least 2 such parallelconfigurations, at least 3 such parallel configurations, at least 4 suchparallel configurations, at least 5 such parallel configurations, atleast 10 such parallel configurations, and so on.

FIG. 20A illustrates an example main-auxiliary branch 2000 including anauxiliary FET stack 2045 and a main FET stack 2040. The auxiliary FETsin the stack 2045 can be independently controlled (e.g., using gate biasnetwork 2 2056 d, 2056 e, 2056 f) or two or more of the auxiliary FETsin the stack 2045 can be controlled using a common auxiliary gate biasnetwork (e.g., by consolidating gate bias network 2 2056 d, 2056 e, 2056f into a single gate bias network). Similarly, the main FETs in thestack 2040 can be independently controlled (e.g., using gate biasnetwork 1 2056 a, 2056 b, 2056 c) or two or more of the main FETs in thestack 2040 can be controlled using a common main gate bias network(e.g., by consolidating gate bias network 1 2056 a, 2056 b, 2056 c intoa single gate bias network).

The stack of auxiliary FETs 2045 and the stack of main FETs 2040 share abody so that a common body bias network 2054 can be used to provide abody bias voltage to the FETs in the main-auxiliary branch 2000. It isto be understood, however, that the main FETs 2040 can share a body andthe auxiliary FETs 2045 can share a body, with the bodies of theauxiliary FET stack 2045 being independent from the bodies of the mainFET stack 2040. In such embodiments, a common body bias network can beused to provide a bias voltage to the body nodes of the auxiliary FETs2045, to the body nodes of the main FETs 2040, or to both the body nodesof the auxiliary FETs 2045 and the body nodes of the main FETs 2040.

The device 2000 can connect the source and drain nodes of the auxiliaryFET stack 2045 and the main FET stack 2040 after N FETs. The number ofFETs in the auxiliary stack 2045 and/or main stack 2040 can be differentfrom one another. The main-auxiliary branch 2000 can include an inputnode (e.g., a source node), an output node (e.g., a drain node), a firstgate node (e.g., an auxiliary gate node), a second gate node (e.g., amain gate node), and a body bias node. Using these five nodes, multipleauxiliary FETs and multiple main FETs can be controlled to provide asignal with improved linearity relative to configurations that do notutilize a main-auxiliary branch configuration.

FIG. 20B illustrates another example main-auxiliary branch 2000 whereinthe gate of a FET in the auxiliary FET stack 2045 is biased using thegate bias network 1 2056 c of a FET in the main FET stack 2040. FIG. 20Cillustrates another example main-auxiliary branch 2000 wherein the gatesof two or more of the FETs in the auxiliary FET stack 2045 are biasedusing the gate bias network 1 2056 c of a FET in the main FET stack2040. FIG. 20D illustrates another example main-auxiliary branch 2000wherein the gates of two or more of the FETs in the auxiliary FET stack2045 are biased using the gate bias network 1 2056 b of two or more FETsin the main FET stack 2040. FIG. 20E illustrates another examplemain-auxiliary branch 2000 wherein the gates of all of the FETs in theauxiliary FET stack 2045 are biased using the gate bias network 1 2056 bof two or more FETs in the main FET stack 2040.

Accordingly, FIGS. 20A-20E illustrate various main-auxiliary branches2000 and configurations for gate bias networks to bias the gates ofactive devices in the main path 2040 and the auxiliary path 2045. Forexample, the gate of each active device in the main path 2040 and thegate of each active device in the auxiliary path 2045 can be biasedusing a dedicated gate bias network. As another example, the gates ofsome of the active devices in the main path 2040 share a common gatebias network with the gates of some of the active devices in theauxiliary path 2045. In such embodiments, the active devices that do notshare a common gate bias network can be biased using individual gatebias networks.

FIG. 21A illustrates an example main-auxiliary device 2100 having afirst auxiliary FET 2145 coupled to a main FET stack 2140 that is inturn coupled to a second auxiliary FET 2145. In this configuration, theauxiliary/main devices are subsets of fingers of a multi-finger devicewherein the auxiliary FETs 2145 are a subset of fingers and the main FETstack 2140 is the other subset of fingers. To illustrate an advantage ofthis configuration, and by way of example, the process details of thefingers used as the auxiliary FET 2145 may be adjusted differently fromthe fingers used as the main FET stack 2140 such that the auxiliary FET2145 can be configured to be in a subthreshold or weak inversion regionwhile the main FET stack 2140 is in a strong inversion region. Asanother example, the process details can be tailored such thatthird-order harmonics (H3) and/or intermodulation distortion (IMD3)generated by the auxiliary devices 2145 is in opposite phase and ofsimilar magnitude with the H3 and/or IMD3 generated by the main device2140 to improve the linearity of the main-auxiliary device 2100.

Another advantage of this configuration is that, with the auxiliary FETs2145 and main FETs 2140 being produced using tailored processes, acommon gate bias network 2156 can be used to control the auxiliary FETs2145 and the main FET stack 2140. Due at least in part to the differentcharacteristics of the auxiliary FETs 2145 and the main FETs 2140,different performance characteristics can be achieved using the commongate bias network 2156. Similarly, the auxiliary FETs 2145 and the mainFETs 2140 can share a body or can tie their respective body nodestogether to be controlled by a common body bias network 2154.

FIG. 21B illustrates an example embodiment of a main-auxiliary device2100 wherein the auxiliary path 2145 is coupled in parallel with themain path 2140. Similar to the device described herein with reference toFIG. 21A, the auxiliary FETs in the auxiliary path 2145 and the mainFETs in the main path 2140 are processed to have properties configuredto result in a reduction in distortions when applying a single gate biassignal to the FETs of the auxiliary path 2145 and the FETs of the mainpath 2140.

The main-auxiliary devices 2100 described with respect to FIGS. 21A and21B can be configured so that the main FETs 2140 operate in a stronginversion region and the auxiliary FETs 2145 operate in a subthresholdor weak inversion region when a tailored gate bias signal is applied bythe gate bias network 1 2156 to the FETs in both the main path 2140 andthe auxiliary path 2145. To accomplish this, the main FETs 2140 can beconfigured to have a threshold voltage that is much lower than thethreshold voltage of the auxiliary FETs 2145. In this way, when a gatebias voltage is applied to the main FETs 2140 that is greater than themain FET threshold voltage, the gate bias voltage can also be less thanthe auxiliary FET threshold voltage, causing the main FETs 2140 tooperate in the strong inversion region and the auxiliary FETs 2145 tooperate in the subthreshold or weak inversion region. The main FETs 2140and/or auxiliary FETs 2145 can be processed to have different physicalcharacteristics to achieve these properties. For example, and withoutlimitation, the channel length, thickness of the gate oxide, channeldoping, gate work function, etc. can be tuned for the main FETs 2140 andthe auxiliary FETs 2145 so that the threshold voltages and othercharacteristics are within targeted ranges.

Similarly, as described herein, the main FETs 2140 and the auxiliaryFETs 2145 can be implemented as a multi-finger device. The physicalcharacteristics of the multi-finger device can be tuned to reducedistortions. For example, properties of the auxiliary FETs can be tunedso that signals generated by the auxiliary FETs reduce or canceldistortions in signals generated by the main FETs. Properties of themulti-finger device that can be tuned include, for example and withoutlimitation, channel length, thickness of the gate oxide, channel doping,gate work function, etc. This allows a single gate bias voltage to beapplied to the multi-finger device that results in some fingersoperating in a strong inversion region while the rest of the fingersoperate in a subthreshold or weak inversion region. This can be done toachieve harmonic cancellation or reduction.

In the main-auxiliary devices described herein, the auxiliary FET(s) canbe replaced with a gate-controlled MOSCAP. This can allow the devices totailor the capacitor characteristics of the auxiliary element.Similarly, in the main-auxiliary devices described herein, the auxiliaryFET(s) can be replaced with a gate-controlled diode. The gate-controlleddiode can be implemented with an independent cathode bias network toprovide similar advantages to those described herein. In someembodiments, this may improve control of the overall device performancecharacteristics. In some embodiments, a combination of gate-controlledcapacitors, gate-controlled diodes, and transistors can form the activedevices of the main-auxiliary branches described herein.

FIGS. 22A and 22B illustrate a simulation demonstrating improvedlinearity for a main-auxiliary device, as described herein. FIG. 22Aillustrates an example main-auxiliary device 2200 implemented as anauxiliary FET in parallel with a main FET with the body nodes beingcoupled to the respective gate nodes through a coupling circuit having adiode, similar to the device 1700 described herein with reference toFIG. 17. A gate bias voltage VG1 is applied to the main FET and a gatebias voltage VG2 is applied to the auxiliary FET.

FIG. 22B illustrates a plot 2250 of simulated results related to thenonlinearity of the device 2200. To obtain the plot 2250, the gate biasvoltage VG1 to the main was fixed and simulations were done over a rangeof gate bias voltages for the auxiliary FET. This was repeated for twogate bias voltages VG1, 3.3 V and 3.5 V. The results of the simulateddata illustrate a marked improvement in linearity at a particular gatebias voltage VG2 applied to the auxiliary FET, which is seen in the plotwhere it dips downward for both VG1 voltages.

Without desiring to be limited to a single theory, it is believed thatthe improvement in the linearity for a particular gate bias voltage VG2is due at least in part to harmonic cancellation. The harmonicsgenerated by the auxiliary FET are similar in magnitude and opposite inphase or sign as those generated by the main FET. At the output, thesegenerated harmonics interfere destructively (e.g., or substantiallycancel each other out) resulting in reduced IMD3 (resulting in improvedlinearity through the device 2200). These perturbations caused by theauxiliary FET can be tailored to cancel or counteract harmonicsgenerated by the main FET by tuning the gate bias voltage of theauxiliary FET.

The characteristics of the improvement in IMD3, and hence linearity, canbe altered by altering the physical characteristics of the auxiliaryFET, by altering the number of active devices used in the auxiliarypath, and/or by altering the operating region of the auxiliary FET(e.g., by applying a targeted gate bias to the auxiliary FET). Thus, bytailoring the auxiliary FET or path characteristics and/or by tailoringthe gate bias(es) to the auxiliary FET or path, the device 2200 andother similar main-auxiliary devices can be configured to improve theoverall performance of the device. In certain simulations, improvementsof about 12 dBm were measured by using gate bias tuning for theauxiliary FET. Accordingly, to derive improved or optimal operatingconditions, a map can be made relating signal power, main gate biasvoltage, and auxiliary gate bias voltage to determine targeted gate biasvoltages for the auxiliary path to achieve targeted performancecharacteristics. In certain implementations, body bias voltages and/orsubstrate bias voltages may also be included in the map to furthertailor operating parameters to achieve targeted performance.

FIG. 23A illustrates an example main-auxiliary device 2300 wherein amain path 2340 includes a plurality of FETs biased using a main gatebias network 2356 a and an auxiliary path 2345 includes a plurality ofFETs biased using an auxiliary gate bias network 2356 b independent ofthe main gate bias network 2356 a. The number of FETs in the main path2340 can be 2 or more FETs. The number of FETs in the stack can beconfigured based on power requirements of the device. For example, thenumber of FETs in the main path 2340 can be relatively high for powerhandling requirements and can be configured to have a relatively largeperiphery to reduce insertion losses. Because the auxiliary path 2345 isin parallel with the main path 2340, the stack number and periphery ofthe auxiliary FETs can be tuned more freely to achieve improvedlinearity. This is due at least in part to the nonlinearity of theauxiliary FETs being a function of the stack number and the FETperiphery. This may be particularly applicable where the main andauxiliary FETs are of the same device type.

In some embodiments, the main gate bias network 2356 a provides a staticgate bias signal. In certain embodiments, the main gate bias network2356 a provides a dynamic gate bias signal. In some embodiments, theauxiliary gate bias network 2356 b provides a static gate bias signal.In certain embodiments, the auxiliary gate bias network 2356 b providesa dynamic gate bias signal. In various implementations, the main gatebias network 2356 a provides a gate bias voltage that is greater thanthe gate bias voltage provided by the auxiliary gate bias network 2356b. The main gate bias network 2356 a can be configured to provide a gatebias voltage that causes the FETs in the main path 2340 to operate in astrong inversion region and the gate bias voltage provided by theauxiliary gate bias network 2356 b is configured to cause the FETs inthe auxiliary path 2345 to operate in a subthreshold or weak inversionregion.

The device 2300 can be used in a switch branch that can be switched onand off. In such implementations, both the main path 2340 and theauxiliary path 2345 can be advantageously configured to have relativelylarge stack numbers for power handling in the off state. To betterimprove performance, the gate bias signal applied to different FETs orsubsets of FETs in the auxiliary path 2345 can differ from one another.This can allow more fine-tuning of the signal characteristics and mayresult in improved performance relative to embodiments where a singlegate bias voltage is applied to all the FETs in the auxiliary path 2345.By way of example, to improve linearity in the “on” state, one or moreFETs in the auxiliary path 2345 can be biased to operate in the weakinversion region, while the remaining FETs are biased to operate in thestrong inversion region. Furthermore, to improve linearity in the “off”state, one or more FETs in the auxiliary path 2345 can be biased tooperate in the weak inversion region, while the remaining FETs arebiased to operate in the accumulation region. Accordingly, it is to beunderstood that the gate bias network 2356 can be configured to applydifferent gate bias signals to different FETs or groups of FETs in theauxiliary path 2345 (similar to the main-auxiliary device 2000 describedherein with reference to FIG. 20A).

FIG. 23B illustrates the main-auxiliary device 2300 of FIG. 23A having afeedback loop configured to adjust the bias provided by the auxiliarygate bias network 2356 b. A coupler 2371 can be included to generate asignal related to the signal at the input node. The coupler 2371 iscoupled to a bias feedback module 2372 that is configured to analyze orprocess the signal from the coupler 2371 and to generate a feedbacksignal. The bias feedback module 2372 sends the feedback to theauxiliary gate bias network 2356 b which determines, generates,modifies, and/or adjusts the gate bias signal to the auxiliary path2345. This can be done to improve performance of the main-auxiliarydevice.

Due at least in part to differences in coupling at the gate, body andbetween source and drain, performance of the main-auxiliary device 2300can change as a function of input signal (e.g., input power, frequency,etc.). Accordingly, the bias feedback module 2372 is implemented toprovide input to the gate bias network 2356 b to dynamically adjust thegate bias voltage to the auxiliary path depending on the input signalcharacteristics.

FIG. 24A illustrates an example main-auxiliary device 2400 having a mainFET stack or path 2440 and an auxiliary FET stack or path 2445, theauxiliary path 2445 including a first subset of FETs, a second subset ofFETs, and a third subset of FETs wherein the first and third subsets ofFETs are biased using a auxiliary gate bias network 2456 c and thesecond subset of FETs is biased using a different auxiliary gate bias2456 b, the first and third subsets of FETs controlling access to theauxiliary path 2445.

The main stack 2440, which includes an n-stack of switches, can beconfigured to serve as a primary signal path between the input node andthe output node. Due at least in part to the nonlinearity of thisconfiguration (e.g., harmonics, intermodulation products, etc.), it maybe desirable to improve performance by at least reducing nonlinearity tomeet specifications for wireless standards or other such standards.Accordingly, the auxiliary path 2445 is included in parallel with themain path 2440. The auxiliary path 2445 includes a nonlinear generator(e.g., the second subset of FETs) and FETs acting as secondary nonlineargenerators and switches controlling access to the auxiliary path 2445.In some embodiments, the total stack of FETs in the auxiliary path 2445would equal or exceed the number of FETs in the main path 2440, howeverthe number of FETs in the auxiliary path 2445 can be less than, thesame, or greater than the number of FETs in the main path 2440.

The first and third subsets of FETs can be configured to have asufficient stack height to withstand voltage and power requirements atboth the input node and the output node. This allows the device 2400 tobe used in both “on” and “off” configurations in a switch application.

The auxiliary path 2445 can be configured to generate a nonlinearity(harmonic, IMD, etc.) that is approximately equal in magnitude andopposite in phase as the nonlinearity of the main path 2440. The neteffect of the signal traveling between the input node and the outputnode through both the main path 2440 and the auxiliary path 2445 isimproved relative to a signal path through the main path 2440 alone. Thenonlinearity generated in the auxiliary path 2445 can be a function ofbiasing and sizing of the nonlinearity generator. The first and thirdsubsets of FETs also contribute to the nonlinearity of the auxiliarypath, aiding in the reduction of distortions generated by the main path2400. The bias signal provided to the second subset of FETs (e.g., theprimary nonlinearity generator) can depend on frequency, input power,temperature, and/or the type of nonlinearity to be cancelled in thedevice 2400.

The first and third subsets of FETs in the auxiliary path 2445 can beused in several ways in the device 2400. For example, when the first andthird subsets of FETs are in the “on” state and the main switch is on,the first and third subsets of FETs can be biased at or near the samevoltage as the FETs of the main path 2440 (e.g., about 2.5 V). In thisarrangement, the distortions (e.g., nonlinearity) of the main path 2440and the auxiliary path 2445 can substantially cancel, thus improvingnonlinearity (harmonic, IMD, etc.,) of the switch.

As another example, when the first and third subsets of FETs are in the“off” state and the main switch on, the first and third subsets of FETsblock the signal from entering the auxiliary path 2440. Thus, the signaltravels from the input node to the output node through the main path2440. This case may be utilized where the nonlinearity of the main path2440 is suitable or in cases where using the auxiliary path 2445 isotherwise undesired. The first and third subsets of FETs can be designed(e.g., have a sufficient stack height) to withstand maximum voltagesseen at the input and output nodes.

As another example, when the first and third subsets of FETs are in the“off” state and the main switch off, the main-auxiliary device 2400 isfully off. The first and third subsets of FETs in the auxiliary path2445 and the main path 2440 can include sufficient stack height towithstand maximum voltage swings at the output node.

FIG. 24B illustrates the main-auxiliary device 2400 of FIG. 24A with theremoval of the third subset of FETs in the auxiliary path 2445. FIG. 24Cillustrates the main-auxiliary device 2400 of FIG. 24A with the removalof the first subset of FETs in the auxiliary path 2445. Theseembodiments have similar functionality to the device 2400 describedherein with reference to FIG. 24A.

Improvement of Linearity Using Auxiliary Paths

FIG. 25 illustrates example circuits that improve signal linearitythrough the use of an auxiliary path. Configuration A represents aswitch path 2500 a that goes through a main path having a main FET 2540a with a gate bias VGS applied to its gate and then through a load toground. The signal is a two-tone signal that includes two frequencycomponents: f₁ and f₂. The switch path 2500 a is represented as a mainnonlinear resistor 2540 b in place of the main FET 2540 a when theswitch is turned on, as shown in the circuit on the right.

The nonlinear resistor 2540 b generates harmonics with a particularmagnitude and phase. By way of example, the magnitude of V_(load) havingthe frequency components f₁ and f₂ is proportional to:

$V_{load} \propto \frac{\partial I_{d}}{\partial V_{ds}}$

with I_(d) being the current through the nonlinear resistor and load. Inaddition, the output of the switch path includes harmonics andintermodulation products where the magnitude of V_(load) includesfrequencies (2*f₁−f₂) and (2*f₂−f₁), e.g., third-order harmonics, whichis represented by the dotted line with an arrow at the load. Third-orderharmonics (H3) and intermodulation products (IM3) (with frequencies(2*f₁−f₂) and (2*f₂−f₁)) are closely related to the third-orderderivative of the current flowing through the main switch path.Accordingly, V_(load) is proportional to:

$V_{load} \propto \frac{\partial^{3}I_{d}}{\partial V_{ds}^{3}}$

with I_(d) being the current through the nonlinear resistor and load.

As described herein, distortions due to harmonics in a switch path canbe reduced through the introduction of an auxiliary path. The auxiliarypath can be used to generate harmonics with similar magnitude andopposite phase to reduce the harmonics of the switch path. This reducesharmonics through the switch path and thereby improves nonlinearity. Byproperly biasing the auxiliary path, a targeted reduction orcancellation of harmonics can be achieved.

Configuration B represents another switch path 2500 b that goes throughthe main FET 2540 a and load to ground but with the addition of anauxiliary FET 2545 a in parallel with the FET 2540 a. The same two-tonesignal is applied that includes the two frequencies f₁ and f₂. When theswitch path 2500 b is on it can be represented as the main nonlinearresistor 2540 b in parallel with an auxiliary nonlinear resistor 2545 bin place of the auxiliary FET 2545 a, as shown in the circuit on theright.

As stated above, the output of the auxiliary nonlinear resistor 2545 bincludes harmonics and intermodulation products where the magnitude ofV_(load) includes frequencies (2*f₁−f₂) and (2*f₂−f₁), e.g., third-orderharmonics, which is represented by the dashed line with an arrow at theload. The third-order harmonics (H3) and intermodulation products (IM3)(with frequencies (2*f₁−f₂) and (2*f₂−f₁)) are closely related to thethird-order derivative of the current flowing through the auxiliarynonlinear resistor 2545 b. Accordingly, V_(load) contributed by theauxiliary path is proportional to:

$V_{load} \propto \frac{\partial^{3}I_{d}^{\prime}}{\partial V_{ds}^{3}}$

with I′_(d) being the current through the auxiliary nonlinear resistor2545 b. The resulting combination of signals from the main nonlinearresistor 2540 b and the auxiliary nonlinear resistor 2545 b can beconfigured to destructively interfere by configuring the bias of theauxiliary FET 2545 a so that the resulting signal has third-orderharmonics that are of a similar magnitude but opposite phase as thesignal out of the main FET 2540 a. In this way, nonlinearity can beimproved at the load and/or the output of the main-auxiliary branchformed by the main path 2540 a and the auxiliary path 2545 a.

It is to be understood that although the switch paths are illustratedwith a single FET, the switch paths can be implemented with stacks ofFETs. For example, the main path 2540 a can include a single FET or aplurality of FETs. Similarly, the auxiliary path 2545 a can include asingle FET or a plurality of FETs, with the number of FETs in the mainpath 2540 a different from the number of FETs in the auxiliary path 2545a.

FIG. 26A illustrates an example FET stack 2600 that is used insimulating the magnitude and phase of third-order harmonics, the resultsof which are illustrated in FIG. 26B. In the FET stack 2600, the totalnumber of FETs in the simulation is 12 with a total width of 3.5 mm anda length of 0.24 μm. The input power of the signal was simulated as 20dBm and V_(body) is 0 V.

As is shown in the plot 2605 of FIG. 26B, the magnitude of thethird-order harmonics varies as a function of the gate voltage. As shownin the plot 2610, the phase of the third-order harmonics also changeswith gate voltage, with a change in phase of 180 degrees at a particulargate voltage. The gate voltage here is about 0.6 V where this transitionoccurs, but it is to be understood that different FET configurationswill have a different gate voltage where this transition occurs.Accordingly, as is illustrated by this simulation, the gate bias of aFET stack can be tailored or tuned to achieve a targeted magnitude andphase of third-order harmonics. This can be done to reduce or cancelthird-order harmonics generated by another FET stack in a switch path,for example, thereby improving linearity through the switch path.

FIG. 27A illustrates a plot 2705 of data corresponding to third-orderintermodulation products (IM3) of a switch path with a main path havinga 12-FET stack biased using a gate bias of 3.5 V. The points labeled“1-stack” correspond to an auxiliary path in parallel with the main pathwhere the auxiliary path includes a single FET. Similarly, the pointslabeled “2-stack” and “3-stack” correspond to auxiliary paths inparallel with the main path where the auxiliary path includes two FETsand three FETs, respectively. The gate bias is varied for the auxiliarypath and the resulting signal characteristics are shown in the plot2705. This data indicates that the FET stack size of the auxiliary pathcan influence the resulting improvements in signal linearity.Accordingly, in addition to tuning the gate bias, the auxiliary path canbe configured to include a targeted or suitable number of FETs toachieve improvements in signal linearity.

FIG. 27B illustrates a plot 2710 of third-order intercept point (IP3) asa function of gate bias applied to a subset of FETs in an auxiliarypath. The data corresponds to a circuit with a main path having a 12-FETstack biased using a gate bias of 3.5 V and an auxiliary path having a12-FET stack where four of these FETs are biased using a fixed bias (1.2V) and the remaining eight FETs were biased using a varying voltage,illustrated in the plot as VG3. The plot 2710 illustrates the effect onIP3 of varying voltage on a subset of the FETs in an auxiliary path.Accordingly, another parameter that can be tuned in an auxiliary path toachieve improved signal linearity is the gate bias applied to a subsetof FETs. In other words, different gate biases can be applied todifferent subsets of FETs in an auxiliary path to achieve targetedreductions in distortions.

Consequently, as described herein, linearity of a signal through aswitch path can be improved through the introduction of an auxiliarypath in addition to a main path. To tune the signal out of the auxiliarypath to achieve a desired or targeted improvement in linearity, one ormore of the following can be done: the number of FETs in an auxiliarypath can be varied, the gate bias applied to one or more FETs in theauxiliary path can be tailored, different gate biases can be applied todifferent subsets of FETs in the auxiliary path, multiple auxiliarypaths can be implemented, auxiliary paths can be implemented in seriesand/or in parallel with a main path, and the like. As is evident fromthe description herein, this list is not exhaustive of the ways toutilize an auxiliary path to improve signal linearity. It should beunderstood that the present disclosure encompasses variations andpermutations of the embodiments described herein.

Examples Related to Implementations in Products

Various examples of main-auxiliary FET devices, circuits based on suchdevices, and bias/coupling configurations for such devices and circuitsas described herein can be implemented in a number of different ways andat different product levels. Some of such product implementations aredescribed by way of examples.

FIGS. 28A, 28B, 28C, and 28D illustrate non-limiting examples of suchimplementations on one or more semiconductor die. FIG. 28A illustratesthat in some embodiments, a switch with a main-auxiliary branch 860 anda bias/coupling circuit 850 having one or more features as describedherein can be implemented on a die 800. The switch with a main-auxiliarybranch 860, for example, can include one or more main-auxiliary brancheshaving the features described herein. The bias/coupling circuit 850, forexample, can include one or more features of the bias networks describedherein. FIG. 28B illustrates that in some embodiments, at least some ofthe bias/coupling circuit 850 can be implemented outside of the die 800of FIG. 28A.

FIG. 28C illustrates that in some embodiments, a switch with amain-auxiliary branch 860 having one or more features as describedherein can be implemented on one die 800 b, and a bias/coupling circuit850 having one or more features as described herein can be implementedon another die 800 a. FIG. 28D illustrates that in some embodiments, atleast some of the bias/coupling circuit 850 can be implemented outsideof the other die 800 a of FIG. 28C.

In some embodiments, one or more die having one or more featuresdescribed herein can be implemented in a packaged module. An example ofsuch a module is shown in FIGS. 29A (plan view) and 29B (side view).Although described in the context of both of the switch with amain-auxiliary branch and the bias/coupling circuit being on the samedie (e.g., example configuration of FIG. 28A), it will be understoodthat packaged modules can be based on other configurations.

A module 810 is shown to include a packaging substrate 812. Such apackaging substrate can be configured to receive a plurality ofcomponents, and can include, for example, a laminate substrate. Thecomponents mounted on the packaging substrate 812 can include one ormore die. In the example shown, a die 800 having a switch with amain-auxiliary branch 860 and a bias/coupling circuit 850 is shown to bemounted on the packaging substrate 812. The die 800 can be electricallyconnected to other parts of the module (and with each other where morethan one die is utilized) through connections such asconnection-wirebonds 816. Such connection-wirebonds can be formedbetween contact pads 818 formed on the die 800 and contact pads 814formed on the packaging substrate 812. In some embodiments, one or moresurface mounted devices (SMDs) 822 can be mounted on the packagingsubstrate 812 to facilitate various functionalities of the module 810.

In some embodiments, the packaging substrate 812 can include electricalconnection paths for interconnecting the various components with eachother and/or with contact pads for external connections. For example, aconnection path 832 is illustrated as interconnecting the example SMD822 and the die 800. In another example, a connection path 833 isillustrated as interconnecting the SMD 822 with an external-connectioncontact pad 834. In yet another example a connection path 835 isillustrated as interconnecting the die 800 with ground-connectioncontact pads 836.

In some embodiments, a space above the packaging substrate 812 and thevarious components mounted thereon can be filled with an overmoldstructure 830. Such an overmold structure can provide a number ofdesirable functionalities, including protection for the components andwirebonds from external elements, and easier handling of the packagedmodule 810.

FIG. 30 illustrates a schematic diagram of an example switchingconfiguration that can be implemented in the module 810 described inreference to FIGS. 29A and 29B. In the example, the switch with amain-auxiliary branch 860 is illustrated as being an SP9T switch, withthe pole being connectable to an antenna and the throws beingconnectable to various Rx and Tx paths. Such a configuration canfacilitate, for example, multi-mode multi-band operations in wirelessdevices. As described herein, various switching configurations (e.g.,including those configured for more than one antenna) can be implementedfor the switch with a main-auxiliary branch 860. As also describedherein, one or more throws of such switching configurations can beconnectable to corresponding path(s) configured for TRx operations. Oneor more of the switchable paths through the switch with a main-auxiliarybranch 860 can be implemented using a main-auxiliary configuration,examples of which have been described herein.

The module 810 can further include an interface for receiving power(e.g., supply voltage VDD) and control signals to facilitate operationof the switch with a main-auxiliary branch 860 and/or the bias/couplingcircuit 850. In some implementations, supply voltage and control signalscan be applied to the switch with a main-auxiliary branch 860 via thebias/coupling circuit 850.

In some implementations, a device and/or a circuit having one or morefeatures described herein can be included in an RF device such as awireless device. Such a device and/or a circuit can be implementeddirectly in the wireless device, in a modular form as described herein,or in some combination thereof. In some embodiments, such a wirelessdevice can include, for example, a cellular phone, a smart-phone, ahand-held wireless device with or without phone functionality, awireless tablet, etc.

FIG. 31 illustrates an example wireless device 900 having one or moreadvantageous features described herein. In the context of variousswitches and various biasing/coupling configurations as describedherein, a switch with a main-auxiliary branch 960 and a bias/couplingcircuit 950 can be part of a module 910. In some embodiments, the switchmodule 910 can facilitate, for example, multi-band multi-mode operationsof the wireless device 900. The switch with a main-auxiliary branch 960can use a main-auxiliary FET device on one or more of the switchablepaths through the switch with a main-auxiliary branch 960. Thebias/coupling circuit 950 can provide gate and/or body biasing to themain-auxiliary FET device(s) implemented in the switch with amain-auxiliary branch 960 using any of the gate and/or body bias networkconfigurations described herein.

In the example wireless device 900, a power amplifier (PA) assembly 916having a plurality of PAs can provide one or more amplified RF signalsto the switch with a main-auxiliary branch 960 (via an assembly of oneor more duplexers 918), and the switch with a main-auxiliary branch 960can route the amplified RF signal(s) to one or more antennas. The PAs916 can receive corresponding unamplified RF signal(s) from atransceiver 914 that can be configured and operated in known manners.The transceiver 914 can also be configured to process received signals.The transceiver 914 is shown to interact with a baseband sub-system 910that is configured to provide conversion between data and/or voicesignals suitable for a user and RF signals suitable for the transceiver914. The transceiver 914 is also shown to be connected to a powermanagement component 906 that is configured to manage power for theoperation of the wireless device 900. Such a power management componentcan also control operations of the baseband sub-system 910 and themodule 910.

The baseband sub-system 910 is shown to be connected to a user interface902 to facilitate various input and output of voice and/or data providedto and received from the user. The baseband sub-system 910 can also beconnected to a memory 904 that is configured to store data and/orinstructions to facilitate the operation of the wireless device, and/orto provide storage of information for the user.

In some embodiments, the duplexers 918 can allow transmit and receiveoperations to be performed simultaneously using a common antenna (e.g.,924). In FIG. 31, received signals are shown to be routed to “Rx” pathsthat can include, for example, one or more low-noise amplifiers (LNAs).

A number of other wireless device configurations can utilize one or morefeatures described herein. For example, a wireless device does not needto be a multi-band device. In another example, a wireless device caninclude additional antennas such as diversity antenna, and additionalconnectivity features such as Wi-Fi, Bluetooth, and GPS.

GENERAL COMMENTS

The present disclosure describes various features, no single one ofwhich is solely responsible for the benefits described herein. It willbe understood that various features described herein may be combined,modified, or omitted, as would be apparent to one of ordinary skill.Other combinations and sub-combinations than those specificallydescribed herein will be apparent to one of ordinary skill, and areintended to form a part of this disclosure.

Some embodiments may be described with reference to equations,algorithms, and/or flowchart illustrations. These methods may beimplemented using computer program instructions executable using one ormore processors or dedicated integrated circuits or chips. In thisregard, each equation, algorithm, block, or step of a flowchart, andcombinations thereof, may be implemented by hardware, firmware, and/orsoftware including one or more computer program instructions embodied incomputer-readable program code logic. As will be appreciated, any suchcomputer program instructions may be executed by any suitableprogrammable processing apparatus to produce a machine, such that thecomputer program instructions implement the functions specified in theequations, algorithms, and/or flowcharts. It will also be understoodthat each equation and/or algorithm and combinations thereof, may beimplemented by special purpose processors or other hardware-basedsystems that perform the specified functions or steps. The variousfunctions disclosed herein may be embodied in computer-executableprogram instructions and/or implemented in application-specificcircuitry (e.g., ASICs or FPGAs).

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Detailed Description using thesingular or plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

The disclosure is not intended to be limited to the implementationsshown herein. Various modifications to the implementations described inthis disclosure may be readily apparent to those skilled in the art, andthe generic principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. The teachings of the invention provided herein can beapplied to other methods and systems, and are not limited to the methodsand systems described above, and elements and acts of the variousembodiments described above can be combined to provide furtherembodiments. Accordingly, the novel methods and systems described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made without departing from the spiritof the disclosure. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the disclosure.

What is claimed is:
 1. A circuit assembly for performing a switchingfunction, the circuit assembly comprising: a branch including a mainpath in parallel with an auxiliary path, both the main path and theauxiliary path having a plurality of field-effect transistors; a firstgate bias network connected to the main path; a second gate bias networkconnected to a first subset of the plurality of FETs of the auxiliarypath; and a third gate bias network connected to a second subset of theplurality of FETs of the auxiliary path, the second gate bias networkand the third gate bias network being independently configurable toimprove linearity of the switching function.
 2. The circuit assembly ofclaim 1 wherein the third gate bias network is configured to bias thesecond subset of the plurality of FETs using a first voltage.
 3. Thecircuit assembly of claim 2 wherein the second gate bias network isconfigured to bias the third subset of the plurality of FETs using asecond voltage different from the first voltage.
 4. The circuit assemblyof claim 2 wherein the second gate bias network is configured to biasthe third subset of the plurality of FETs using a second voltage equalto the first voltage.
 5. The circuit assembly of claim 1 wherein thethird gate bias network is configured to turn off the second subset ofthe plurality of FETs of the auxiliary path to improve linearity of theswitching function.
 6. The circuit assembly of claim 1 wherein thesecond subset of the plurality of FETs of the auxiliary path includes agreater number of FETs than the first subset of the plurality of FETs ofthe auxiliary path.
 7. The circuit assembly of claim 1 wherein thesecond subset of the plurality of FETs of the auxiliary path includesthe same number of FETs as the first subset of the plurality of FETs ofthe auxiliary path.
 8. The circuit assembly of claim 1 wherein the firstgate bias network is configured to bias the main path in a stronginversion region, the second gate bias network is configured to bias thefirst subset of the plurality of FETs of the auxiliary path in a weakinversion region, and the third gate bias network is configured to biasthe second subset of the plurality of FETs of the auxiliary path in aweak inversion region.
 9. The circuit assembly of claim 1 wherein thesecond gate bias network is configured to bias the first subset of theplurality of FETs of the auxiliary path to generate third-orderharmonics or third-order intermodulation products that are opposite inphase to third-order harmonics or third-order intermodulation productsgenerated by the main path.
 10. The circuit assembly of claim 9 whereinthe third gate bias network is configured to bias the second subset ofthe plurality of FETs of the auxiliary path to generate third-orderharmonics or third-order intermodulation products that are opposite inphase to third-order harmonics or third-order intermodulation productsgenerated by the main path.
 11. The circuit assembly of claim 1 whereinthe branch is coupled between a series arm and a reference potentialnode in a shunt configuration.
 12. The circuit assembly of claim 11wherein the second gate bias network and the third gate bias network areconfigured to reduce capacitive nonlinearity of the switching function.13. A circuit assembly for performing a switching function, the circuitassembly comprising: a branch including a main path in series with anauxiliary path, both the main path and the auxiliary path having aplurality of field-effect transistors; a first gate bias networkconnected to the main path; a second gate bias network connected to afirst subset of the plurality of FETs of the auxiliary path; and a thirdgate bias network connected to a second subset of the plurality of FETsof the auxiliary path, the second gate bias network and the third gatebias network being independently configurable to improve linearity ofthe switching function.
 14. The circuit assembly of claim 13 wherein thethird gate bias network is configured to bias the second subset of theplurality of FETs using a first voltage.
 15. The circuit assembly ofclaim 14 wherein the second gate bias network is configured to bias thethird subset of the plurality of FETs using a second voltage differentfrom the first voltage.
 16. The circuit assembly of claim 14 wherein thesecond gate bias network is configured to bias the third subset of theplurality of FETs using a second voltage equal to the first voltage. 17.The circuit assembly of claim 13 wherein the third gate bias network isconfigured to turn off the second subset of the plurality of FETs of theauxiliary path to improve linearity of the switching function.
 18. Thecircuit assembly of claim 13 wherein the second subset of the pluralityof FETs of the auxiliary path includes a greater number of FETs than thefirst subset of the plurality of FETs of the auxiliary path.
 19. Thecircuit assembly of claim 13 wherein the second subset of the pluralityof FETs of the auxiliary path includes the same number of FETs as thefirst subset of the plurality of FETs of the auxiliary path.
 20. Thecircuit assembly of claim 13 wherein the first gate bias network isconfigured to bias the main path in a strong inversion region, thesecond gate bias network is configured to bias the first subset of theplurality of FETs of the auxiliary path in a weak inversion region, andthe third gate bias network is configured to bias the second subset ofthe plurality of FETs of the auxiliary path in a weak inversion region.21. The circuit assembly of claim 13 wherein the second gate biasnetwork is configured to bias the first subset of the plurality of FETsof the auxiliary path to generate third-order harmonics or third-orderintermodulation products that are opposite in phase to third-orderharmonics or third-order intermodulation products generated by the mainpath.
 22. The circuit assembly of claim 21 wherein the third gate biasnetwork is configured to bias the second subset of the plurality of FETsof the auxiliary path to generate third-order harmonics or third-orderintermodulation products that are opposite in phase to third-orderharmonics or third-order intermodulation products generated by the mainpath.
 23. The circuit assembly of claim 13 wherein the branch is coupledbetween a series arm and a reference potential node in a shuntconfiguration.
 24. The circuit assembly of claim 23 wherein the secondgate bias network and the third gate bias network are configured toreduce capacitive nonlinearity of the switching function.
 25. Thecircuit assembly of claim 13 wherein the first subset of the pluralityof field-effect transistors of the auxiliary path is coupled to an inputof the branch, the second subset of the plurality of field-effecttransistors of the auxiliary path is coupled to an output of the branch,and the plurality of field-effect transistors of the main path arecoupled between the first subset and the second subset of the pluralityof field-effect transistors of the auxiliary path.
 26. A radio-frequency(RF) module comprising: a packaging substrate configured to receive aplurality of devices; and a circuit assembly mounted on the packagingsubstrate, the circuit assembly including a branch including a branchincluding a main path in parallel with an auxiliary path, both the mainpath and the auxiliary path having a plurality of field-effecttransistors, a first gate bias network connected to the main path, asecond gate bias network connected to a first subset of the plurality ofFETs of the auxiliary path, and a third gate bias network connected to asecond subset of the plurality of FETs of the auxiliary path, the secondgate bias network and the third gate bias network being independentlyconfigurable to improve linearity of the switching function.
 27. The RFmodule of claim 26 wherein the first gate bias network is configured tobias the main path in a strong inversion region, the second gate biasnetwork is configured to bias the first subset of the plurality of FETsof the auxiliary path in a weak inversion region, and the third gatebias network is configured to bias the second subset of the plurality ofFETs of the auxiliary path in a weak inversion region.
 28. A wirelessdevice comprising: a transceiver configured to process radio-frequency(RF) signals; an RF module in communication with the transceiver, the RFmodule including a circuit assembly including a branch including abranch including a main path in parallel with an auxiliary path, boththe main path and the auxiliary path having a plurality of field-effecttransistors, a first gate bias network connected to the main path, asecond gate bias network connected to a first subset of the plurality ofFETs of the auxiliary path, and a third gate bias network connected to asecond subset of the plurality of FETs of the auxiliary path, the secondgate bias network and the third gate bias network being independentlyconfigurable to improve linearity of the switching function; and anantenna in communication with the RF module, the antenna configured tofacilitate transmitting and/or receiving of the RF signals.
 29. Thewireless device of claim 28 wherein the first gate bias network isconfigured to bias the main path in a strong inversion region, thesecond gate bias network is configured to bias the first subset of theplurality of FETs of the auxiliary path in a weak inversion region, andthe third gate bias network is configured to bias the second subset ofthe plurality of FETs of the auxiliary path in a weak inversion region.30. The wireless device of claim 28 wherein the circuit assembly isimplemented in a series arm of a multi-pole, multi-throw switch.